- Four explosions in as many days have rocked the Fukushima Daiichi nuclear power plant, which was damaged by Friday's huge earthquake
- Officials say radiation levels, which spiked earlier on Tuesday, have stabilised but remain above safe limits
- The Tokyo stock market has plummeted for a second day despite billions of dollars being pumped into the banking system
- Food, water and fuel are reported to be running short in some parts of Japan and large swathes of the country remain without power
- Live page reporters: Stephanie Holmes, Becky Branford, Yaroslav Lukov, Anna Jones and David Gritten
- All times in GMT
Back to the ongoing crisis at the Fukushima Daiichi nuclear plant: the Kyodo news agency reports that engineers are spraying boric acid to prevent "recriticality" - presumably, the resumption of a self-sustaining nuclear chain reaction - at reactor 4.
Finally, more than 76,000 buildings have been damaged, including at least 6,300 completely destroyed, NHK says.
About 850,000 households in the north are still without electricity in near-freezing weather, according to the Tohuku Electric Power Company. The government says at least 1.5 million households lack running water.
NHK also says more than 440,000 people are currently living in 2,400 evacuation shelters in north-eastern and central prefectures. Some shelters have yet to receive food and water and other essential supplies.
The official death toll from Friday's earthquake and tsunami has risen to 3,373, police tell NHK television. In Miyagi prefecture, 1,619 deaths have been confirmed, and 2,011 people remain unaccounted for. In the town of Minamisanriku, about 1,000 bodies have been discovered. Another 8,000 people, or nearly half the town's population, are missing. Police have found several hundred bodies on the beaches of the Oshika peninsula. Iwate prefecture has 1,193 confirmed deaths, including 373 deaths from the cities of Rikuzentakata and Ofunato. Fukushima prefecture has meanwhile reported 506. More than 7,000 people remain unaccounted for.
Meanwhile the Tokyo Electric Power Company has said an estimated 70% of the nuclear fuel rods inside reactor 1 at Fukushima Daiichi have been damaged, along with 33% of the rods inside reactor 2, the Kyodo news agency reports. The reactors' cores are believed to have melted partially when their cooling systems malfunctioned.
Minoru Ogoda, a spokesman for the Japanese nuclear safety agency, tells AFP: "We have received information from [the Tokyo Electric Power Company] that the fire and smoke is now invisible and it appears to have gone out of its own accord." An explosion on Tuesday morning damaged reactor 4's building and sparked a fire in its spent fuel storage pond. The reactor had been shut down before Friday's earthquake for maintenance, but its spent nuclear fuel rods were stored on the site.
The Japanese government is now saying the fire in reactor 4 is "under control", according to the AFP news agency.
A spokesman for the Tokyo Electric Power Company (Tepco) has said: "At around 0545 today, our employee carrying batteries to the control room discovered smoke billowing from the building of reactor 4 [at Fukushima Daiichi]."
The BBC's Roland Buerk in Tokyo says that on the surface, the city is calm. "But look a bit closer and the concern people are feeling here about radiation leaks at the Fukushima nuclear power station is clear,"
Kirby Kemper, a nuclear physics professor at Florida State University, has praised the Fukushima workers who have stayed behind to battle the fires and leaks. "There are 40 people or so that are in the process of risking their lives trying to pump sea water into these plants. They are real heroes. If they get the plants full of sea water, then things will cool down and we'll be OK," he told Reuters.
Officials said the fire new erupted, or reignited, because a blaze at the plant earlier had not been extinguished.
Japanese news agency Kyodo reports that the storage pool in reactor four - where the spent fuel rods are kept - may be boiling. Tepco says readings are showing high levels of radiation in the building, so it is inaccessible. Radiation levels had fallen late on Tuesday but remained abnormal.
The BBC's Roland Buerk in Tokyo says people in the capital are uneasy and anxious about a threat they cannot see or smell and that moves with the wind. While some people say they trust the government to tell them what is going on, others are saying they don't believe it when they are told there is no immediate danger.
A reminder that reactor four was not in operation at the time the earthquake struck, but was being used to store spent fuel rods.
Tepco spokesman Hajimi Motujuku says the fire at reactor four is in the outer housing of the containment vessel. Its cause is not yet known, AP reports.
Writing in the
Martin Wolf says that if any country is inured to such tragedies, it is Japan. "Its people will cope. This seems certain. A bigger question is whether something more positive might emerge from the tragedy."
Kazuto Inai from Yokohama City writes: "I was told by the general manager of my company today that all colleagues had to stay at home this week since the situation of radiation from Fukushima nuclear might get worse. So this afternoon I left the office, located near the Tokyo bay area. We have had another strong quake, the epicentre of which is the east of Shizuoka Prefecture, the west area from Tokyo but there is no problem so far. I am not worried even though I have been told to stay home. We are just working from home."
US President Barack Obama tells ABC-affiliate
it is "very important to make sure that we are doing everything we can to ensure the safety and effectiveness of the nuclear facilities" in the US. "I've already instructed our Nuclear Regulatory Agency to make sure that we take lessons learned from what's happened in Japan and that we are constantly upgrading how we approach our nuclear safety in our country," he added.
Mark Dubois, of Medecins Sans Frontieres, says many displaced people are starting to suffer in the cold winter weather. A lot of elderly people have also found their regular medical treatment has been interupted: "People who have hypertension, diabetes, other chronic illnesses where they would normally have to go and see their doctors on a regular basis. We're seeing a lot of that and we're having to respond to that," he told the BBC.
The BBC's Matt Frei in Tokyo says spent fuel rods in reactors five and six are also now believed to be heating up.
The Wall Street Journal's
Lam Thuy Vo
tweets: "Came to Tokyo via bus ride with people from #Sendai. Flights to Tokyo/Osaka booked until April, 100 standby tix sold, and now emergency buses."
Tepco has confirmed that a fire broke out at reactor four in the early hours of Wednesday morning. Smoke is pouring from the reactor, a spokesman told reporters.
Lyn Francis, in the UK, told the BBC she received a text message from a friend who is trapped by floods on the fifth floor of a university building in Ishinomaki. "He and his colleagues have very little - or by now possibly no - food, no water and no heating. I received a text from him at 2100 GMT it read: 'It's bad. Love to you all'. It sounds like the last text someone would write if they were dying."
Japan is a proud country, reluctant to accept outside help at the best of times, says our correspondent. But these are the worst of time, he says, and outside assistance is now arriving, in the form of a team of US nuclear experts who are joining Japanese efforts to prevent a nuclear catastrophe.
The BBC's Matt Frei in Tokyo says the city is at the mercy of events it simply cannot control. Japan now has the unique status in human history of being confronted with an earthquake, tsunami and nuclear disaster within days, he says.
Tepco says efforts are underway to tackle the fire inside the building which houses the number four reactor, Reuters reports.
More on those two workers reported to be missing from Fukushima. A national nuclear safety agency spokesman, Masami Nishimura, said they went missing on Friday, the day the quake and tsunami struck, not after Tuesday's explosion, AFP reports.
Flames are rising from the reactor, AP reports.
AFP is reporting a new fire at the number four reactor at the Fukushima Daiichi nuclear plant.
Officials say there is no risk from radiation in that region at present, and warn people could be exposing themselves to other health dangers by needlessly taking iodine supplements.
The authorities in the US and Canada have warned people there is no need to rush to buy iodine tablets. Chemists along the western coast of North America have reported a soaring demand for the tablets, which prevent give the body sufficient iodine that is stops absorbing any externally which may be contaminated by radiation.
Prof Ray Powles, head of the group's Nuclear Accident Committee (NAC), told AFP the chances of large numbers of people being exposed to extensive levels of radiation were "remote" but added: "If it really does evolve into a major radiation problem and there are several hundred victims, then I think that the humanitarian response on a worldwide basis will be huge." Victims would need to receive bone marrow transports, he said, or antibiotics and blood transfusions.
The European Group for Blood and Marrow Transplantation (EBMT) has asked 500 bone marrow transplant centres to be ready to treat Japanese victims of the nuclear accident if needed. In its request, the group said there was real concern that a "significant number of workers attempting to control the damaged nuclear power station" in Japan may receive "doses or whole body radiation over the next week or so," AFP reports.
Mr Deiss continued: "Through Japan, the region and the entire world are affected. The international community must therefore show solidarity and provide assistance to the Japanese people and government in order to help them overcome this major challenge as quickly as possible. Our efforts should extend to the other countries of the region that were affected by the catastrophe."
Assembly President Joseph Deiss said that only a month ago, the members had met to discuss risk prevention. "Since then, reality in the form of the earthquake in New Zealand, now the disaster affecting Japan has reminded us of the importance of prevention, but also the difficulty of predicting every danger. Even Japan, one of the best prepared countries can be devastated."
The United Nations General Assembly paused for a minute's silence on Tuesday evening, to remember the victims in Japan.
Lee Tin-lap, a toxicologist at Hong Kong university, told Reuters the radiation was not immediately dangerous, but that there could be longer term effects. "You are still breathing this into your lungs, and there is passive absorption in the skin, eyes and mouth and we really do not know what long-term impact that would have," he said.
Tokyo Electric Power Co (Tepco) has just announced it is abandoning the plan to use helicopters to drop water as it would be too impractical, AP reports. It said other options were being considered, including using fire engines. Our correspondent said there had been concerns over the proposal, not least because of the possible health impact for the helicopter pilots.
The BBC's Roland Buerk in Tokyo says that as well as dropping water from helicopters onto the fourth Fukushima reactor - in an attempt to cool it down - officials are considering removing the outer panels, to reduce the build up of hydrogen which caused the previous explosions.
Reuters has reported that two workers are missing at the Fukushima plant - they have not been named but Japan's nuclear safety agency said they had been in the turbine area of reactor four.
The BBC's medical correspondent, Fergus Walsh,
writes in his blog:
"So what are the risks at present to those living near the Fukushima Daiichi nuclear plant? Scientists I have spoken to say we cannot give a clear answer yet because we don't know enough about the amount and type of radioactive material that has leaked. Nonetheless, most experts seem to suggest the danger to the public is low."
Canada's Prime Minister, Stephen Harper, has downplayed the risk of radiation to people living on its Pacific Coast. "There is no evidence of a scenario that presents any risk to this country in terms of... radiation or nuclear fallout coming to Canada," he told reporters. Residents of the western province of British Columbia have been ignoring the advice of local health authorities and emptied pharmacies in Vancouver and Victoria of anti-radiation medicines such as potassium iodide, the AFP news agency reports.
The BBC's Aidan Lewis adds: "The operator of the plant, Tokyo Electric Power Company (Tepco), has given no information about their employees. But one expert suggested that workers who have retired or are based in other parts of the country are likely to be called in as the crisis drags on. Those already on duty are being hailed as heroes."
But David Richardson, a professor of epidemiology at the university of North Carolina who has studied the long-term health risks for nuclear plant workers, said those at Fukushima would still be exposed to Gamma radiation that passed through the body like an X-ray. And he said the doses of radiation received in an hour could be higher than those that nuclear workers in the US are generally exposed to over the course of an entire career. "These workers in a few hours are getting fairly high doses I would say by contemporary standards for worker protection and that's likely to pose some risks down the line. To my knowledge there's not a good way after exposure of trying to protect somebody from the risks of a subsequent later cancer."
A small group of workers have been battling around the clock to stave off disaster at Fukushima Daiichi. The BBC's Aidan Lewis says: "The few dozen who are left have faced explosions and fires as they rush to pump sea water into overheated reactors. The workers are being rotated in and out, to try to limit their exposure to radiation. They are also assumed to be wearing sophisticated protective clothing."
A level 6 incident is a "serious accident" which results in a "significant release of radioactive material likely to require implementation of planned countermeasures". The 1957 Kyshtym disaster was classified as level 6. An explosion at a Soviet military nuclear waste reprocessing plant in the Russian Urals led to large off-site release of radioactive material.
The US-based Institute for Science and International Security (ISIS) has said it agrees with the assessment of France's Nuclear Safety Authority (ASN) that the incident at Fukushima should be classified as level 6 on the International Nuclear Event Scale (INES), one below Chernobyl. Following a number of explosions and a fire at the plant which released dangerous levels of radiation, ISIS said the situation had "worsened considerably" and was now closer to a level 6 event. "It may unfortunately reach a level 7," it added.
Mr Amano said he still believed the situation in Japan was different from the Chernobyl disaster, even though recent events were "worrying". "It is difficult to foresee whether the future developments will be a worsening or improving of the situation," he added. "We do not know. There are mixed indications."
The head of the International Atomic Energy Agency (IAEA), Yukiya Amano, has said he wants more timely and detailed information about developments at the Fukushima Daiichi nuclear plant from the Japanese authorities. "The problem is very complicated, we do not have all the details of the information so what we can do is limited," he told a news conference in Vienna, according to Reuters. "I am trying to further improve the communication." Mr Amano said the UN agency planned to send a team of experts to Japan, possibly to help with environmental monitoring.
Japan faces a recovery and reconstruction bill of at least $180bn (£112bn), or 3% of its annual economic output, according to initial estimates from Credit Suisse. That is more than 50% higher than the commonly accepted cost of the 1995 earthquake in Kobe, which killed 6,000 people. Some extreme projections of the longer-term costs run as high as $1 trillion over several years, the Reuters news agency reports.
The US Nuclear Regulatory Commission (NRC) has said Japan's response to the crisis at the Fukushima Daiichi power plant has been in line with its own safety policies. Japan has recommended evacuation up to 20km (12 miles) around the reactors and advised people within 30km (19 miles) of the reactor to remain inside. "Those recommendations parallel the protective actions the United States would suggest should dose limits reach 1 rem to the entire body and 5 rem for the thyroid, an organ particularly susceptible to radiation uptake. The currently reported Japanese radiation measurements are well below these guidelines,"
a statement said
Ms Hosomi adds: "There was a 6.4 earthquake in the Shizuoka area, where I am from and my family are now. This is near the Hamaoka nuclear plant, which is still operating. It has been predicted that the Shizuoka area will have an eight level earthquake in the near future, due to the pressure from two [tectonic] plates. We must put pressure on the Japanese government to stop the operation of the Hamaoka plant, which could cause the same damage as the plant at Fukushima if further earthquakes happen. We don't want the same situation happening again."
Yukiko Hosomi, who lives in Bristol but has family in the Shizuoka prefecture of Japan, not far from a nuclear plant similar to the one at Fukushima, tells the BBC: "I am very concerned and worried about the situation. I have been in touch with people in Japan, but I am utterly shocked at their 'optimism' and the lack of information about this critical situation. I have been following both international and Japanese media and the difference of information is unbelievable. The Japanese government and media are not telling the truth, underestimating the people's capacity to cope."
Aftershocks have continued to shake Japan, days after the massive magnitude 9 earthquake that triggered a devastating tsunami on Friday. More than 20 have been larger than magnitude 6.0. The BBC News website has
plotted the tremors on a map
so you can see when and where they have struck.
There have been a handful of joyous moment for rescue workers as they pulled people from the wreckage. One 20-year-old man was
carried away on stretcher in Ishimona,
apparently in reasonable health, after being trapped for 96 hours.
Takashi Honda, a rescue worker searching for survivors in Otsuchi, told AP earlier he was not giving up hope of finding survivors: "People don't die easily. That is why we are doing our best. We will continue to spot areas which have not been searched yet."
The BBC's Chris Hogg in Tokyo says that, in the early hours of Wednesday morning in Japan, there are still concerns about the number four reactor at Fukushima. Officials fear the water level is still too low, meaning the spent fuel rods stored there are exposed to the atmosphere.
The BBC's Gavin Lee is travelling with the British team. He reported seeing ships on top of houses and hundreds of vehicles, including a school bus, in piles of debris.
British search and rescue teams are searching for survivors in the badly hit town of Ofunato in Iwate prefecture.
This interactive image
shows the scale of what they are facing.
The head of the International Energy Agency (IEA), Nobuo Tanaka, has said the Japanese disaster could hold back attempts to address climate change through developing nuclear technology. "While I understand the public reaction, I am concerned about the effect it could have on support for this technology, given its important role in achieving both energy security and a low-carbon economy," he told reporters in Oslo.
The White House has said it is not advising Americans to leave Tokyo at present.
The BBC's Chris Hogg in Tokyo says there are now believed to have been four blasts at Fukushima. The fourth reportedly occured in reactor four, where spent fuel rods are stored, he says.
Writing in the
Wall Street Journal,
Yoree Koh says Japan's Prime Minister Naoto Kan may not emerge unscathed from the crisis. "As fears over a possible nuclear catastrophe reached new heights Tuesday, Mr Kan's brief public appearance did little to tamp concerns."
The president of the EU Council, Herman Van Rompuy, said Europe is ready to assist Japan if asked. "An earthquake powerful enough to make the world wobble on its axis, a massive tsunami, an emergency in nuclear power stations. Any one of these would be a tragedy. Thousands of people have died and this has turned this tragedy into a catastrophe," he said of the nuclear crisis.
"There is little left but roofs piled high, the wooden shards of the homes ripped up, and the odd family photo protruding from the mud," says our correspondent. "The aftershocks go on, there is snow and it is getting colder and the thousands cut off have a daily battle just to live."
The BBC's Alastair Leithead has been in Minami Sanriku, one of the worst affected areas. There is little to do with the miles and miles of destruction than to begin clearing up, he says. Residents have no power, clean water, phones or fuel but are improvising, pooling their resources and "doing what Japan does, stoically getting on with surviving".
Haruka Endo from Saitama writes: "Although my home is located in one part of areas that Tokyo Electricity Company designated a blackout area, it didn't happen today. My house is a little bit dark and cold but when I think about the sufferers, it's not a problem. I heard that lots of people are trying to save electricity like I'm doing. I strongly feel a sense of unity from Japanese people."
tweets: "Tokyo is a ghost town tonight. No people on the streets. Even the entertainment districts. Eerily quiet. But Tokyo is amazing. Even with blackouts, train problems, no rioting, no looting, no robberies."
Airlines including British Airways, Air France, Swiss, KLM and Alitalia say all their flights to Japan are operating as scheduled but have advised customers to check the status of their flights before heading to the airport.
India has ordered imported Japanese food products to be tested for radioactivity, food safety authorities have said, according to Reuters. Thailand, South Korea, Hong Kong, Singapore and the Philippines have already ordered similar tests.
The Japanese-born head of the International Energy Agency chief has warned that the cost of fighting global warming will rise if there is a backlash against nuclear power. "I think it is very difficult (to fight global warming), even impossible, without using nuclear power," Nobuo Tanaka said, according to Reuters in Oslo.
Rebuilding the damage to Japan could take half a decade, according to one World Bank expert. "Reconstruction after the 1995 Kobe earthquake in Japan took a bit less than five years, I would expect reconstruction here to last five years," Abhas Jha said, according to Reuters.
Europe's Energy Commissioner Guenther Oettinger says Japan's nuclear disaster is an "apocalypse", adding that Tokyo has almost lost control of events at the Fukushima power plant, AFP report.
The Wall Street Journal's Japan blog
says that according to Russian news sources Prime Minister Vladimir Putin - a renowned judo enthusiast - has invited the Japanese national judo team, and their families, to train in Russia.
Charles D, writing on his Expat in Japan blog, says:
"It is rather surreal to have to continue going to work when no less than three nuclear plants are near meltdown only 150 miles away. So, I have tried to become knowledgeable about BWRs, cesium microsievert levels, iodine, containment vessels, etc.."
Tom Kaneko in Cambridge, UK writes: "My mother lives and works in Koriyama, and is keen to point out that those being checked for radiation are people who have been evacuated from nearer the nuclear power plant - Koriyama is one of the reception centres. Koriyama residents are not being routinely checked."
International Atomic Energy Agency
tweets: "IAEA confirms 6.1 earthquake two hours ago in eastern Japan, Hamaoka nuclear plant (100km from epicentre) is unaffected: http://j.mp/ffzwEy "
After Germany decided to suspend its operations at its older nuclear power stations, the chief of German utilities firm E.ON has warned that the "new unbalance" will increase the system's risk. "Minor accidents can have major implications," Johannes Teyssen said from Brussels, according to Reuters.
The head of the UN's nuclear watchdog said that there was a "possibility of core damage" at the No. 2 unit of the damaged Fukushima power plant. The damage would be "less than five percent", IAEA chief Yukiya Amano said, according to Reuters.
The radiation plume from the damaged nuclear power could reach Tokyo, according to predictions from a US not-for-profit group, the Union for Concerned Scientists.
Our reporter Clive Myrie, in Yamagata, says that it has started to snow, which will make access to remote areas affected by the quake even more difficult. More snow is forecast over the coming days.
The BBC's Matt Frei, in Tokyo, spoke to one UK banker based in the city who wants to move further away, but cannot. "Unfortunately, we cannot leave," Mark Law told him. "My daughter is in hospital for a pre-planned operation and she needs aftercare following the operation. So it's a bid of a bad situation".
The European Union has decided to conduct "stress tests" on the continent's nuclear power plants, the bloc's energy chief Guenther Oettinger said, according to AFP.
Eric Ouannes of Medecins Sans Frontieres (MSF) told BBC's Newshour earlier: "In front of such a disaster, even the most organised groups have difficulties reaching some areas. There are pockets of people that have not received any aid for the moment in remote places, where roads and infrastructure has been destroyed. So we are currently looking at these locations and reaching in some of them to try and provide medical support there."
Tom Trevethan in Shinjuku says: "I managed to get a lift this morning with a colleague back to Tokyo from Sendai. It took nine hours, via Yamagata and Niigata. I am staying in Shinjuku now, I've booked a flight with Virgin on Thursday - praying they will still be flying to Narita airport."
The UK's emergency helpline on Japan - +44 (0) 20 7008 0000 - has taken more than 5480 calls, says the FCO.
The FCO says it has established a 24-hour Consular Response Centre at the Holiday Inn in Sendai. Full information for UK nationals in Japan is available
on the embassy's website.
The UK Foreign Office has issued an update on its work in Japan. The UK Search and Rescue team have set up base with US teams in Sumita, near Ofunato. "This morning at 0600 local time the full team was deployed to the centre of the disaster zone in Ofunato. The team cleared a large industrial district and residential area. Although bodies were recovered, no survivors have been found so far. The team will now be tasked overnight with new operations."
Japan's Deputy Cabinet Secretary for Public Relations
tweets: "On the 16th, 8 experts of U.S. Nuclear Regulatory Commission will arrive in Japan. They will give technical advice to respond to Fukushima."
China's quality watchdog says it has "asked local bureaus to strengthen their risk analysis of the entry of radioactive materials, and to earnestly monitor for nuclear and radioactive materials at entry ports".
Romen Barua in Tokyo writes: "I work for a British based recruitment company and we are closed for the rest of the week. Apart from the threat of power outages (have not actually heard of anyone in Tokyo experiencing this) and reduced transportation access, I have not experienced any difficulty so far. I am yet to be convinced that the radiation will be lethal as I sit 250km away in Shibuya, Tokyo. A lot of my friends have headed south west to Kansai for the comfort of an extra 500km breathing space but I am happy here unless things worsen."
James Brown in Fukushim-Shi, says: "We just got hit with another good rattler here in Fukushima - it was a level 4-5 here and 6 elsewhere else in Japan. We're getting hit with constant shakes all the time sometimes regularly, every 30-90 secs. I was actually in Tokyo on Friday when the quake struck here on business. My wife (who is two months or so pregnant) was home here in Fukushima."
US Treasury Secretary Timothy Geithner has offered assistance to Japan's finance ministry and the Bank of Japan, Reuters reports.
"The most important thing we can do is to cook," one woman told our correspondent. "We use the rice. We can get by with that."
The BBC's Rachel Harvey is in a village close to the earthquake zone. She has witnessed emotional reunions, as people discovered their friends had survived the tsunami, and saw locals setting up community kitchens to cook food in the open air.
If you want more information on the health implications of radiation exposure, we have a
Q&A on the issue,
which looks at the current risk, the possible long-term effects and treatment available.
Meanwhile, NHK television has more on the elderly man and woman found by rescue crews under collapsed buildings after more than three days. It reports that the man was pulled from the rubble in the city of Ishinomaki in Miyagi prefecture, 96 hours after the earthquake and tsunami. The woman, who is 70 years old, was found in the wreckage of her home in the town of Otsuchi in Iwate prefecture, 92 hours after the disaster. She is being treated for hypothermia at a hospital in nearby Kamaishi. Doctors say she is in a stable condition.
Michel Jarraud, the secretary general of the UN's World Meteorological Organisation, tells the BBC that at the moment, the dominant wind is blowing any radioactive particles out over the Pacific Ocean. His organisation is monitoring the situation closely, he adds.
Jeremy O'Neill, a Canadian trying to get home from Urayasu in Chiba prefecture, tells the BBC: "As a foreigner here, there is a growing sense of feeling trapped. People are handling the matter in different ways; some are panicking while others are turning a blind eye. All the while the uncertainty grows more palpable, with a lack of definitive information from authorities. That is the worst part - the uncertainty. I am from Vancouver in Canada and have been out here since August 2010. I was meant to be staying here until April 2011 but I just want to get home now. The situation doesn't seem to be improving here. I have booked a flight home for tomorrow but many of the flights are getting cancelled - I feel trapped."
A spokesman for Japan's meteorological agency says he does not know if there is a link between the strong earthquakes on Tuesday - including one of 6.0 magnitude - and Friday's massive 9.0-magnitude tremor. He says the epicentres were quite far apart.
Tepco says it may start pouring water from a helicopter over Fukushima Daiichi's reactor four in the next few days, to cool the spent-fuel pool.
Our correspondent says Japan's economic recovery could take much longer than after other disasters, partly because the destruction is so widespread but also because it has called into question the country's dependency on nuclear power. Some or all of Japan's nuclear infrastructure may have to be rebuilt in light of the events, he says, at vast expense.
BBC's Mark Gregory has been looking at the economic impact of the quake. Early estimates have put the cost at £112bn ($180bn), equal to 3% of national output. "That's a large burden for a nation that even before last week's disaster had the highest public debt - 200% of GDP - of any advanced economy," he says.
More from US Energy Secretary Stephen Chu. He told lawmakers that Americans "should have full confidence that the United States has rigorous safety" rules and that nuclear plant builders "clearly consider things like tsunamis ... and earthquakes". He added: "Whenever there's an incident such as what's happening in Japan, we have to pay very close attention to that, think very hard."
Andrew Coad, from Tokyo, writes: "For German Foreign Minister Guido Westerwelle to describe the nuclear events in Japan as an "apocalypse" is irresponsible in the extreme. At this point in time there has been no confirmed reports of any leakage of core material into the environment. So far it has been contained."
A 30km (18 mile) no-fly zone is in place around Fukushima, says the IAEA.
The IAEA says Monday's blast at Fukushima may have affected the integrity of the containment vessel - there are fears of more serious radioactive leaks if happen.
Following earlier reports, it appears there has been more than one strong aftershock in Japan - AP reports two tremors measuring over 6.0 within three minutes of each other.
Mr Juppe said Japan could count on the continuing support of the international community.
Foreign ministers meeting at the G8 have praised Japan for its handling of the crisis. France's Alain Juppe said: "We expressed our admiration for the dignity and the courage shown by the Japanese during this unprecedented ordeal. We expressed our confidence in the way the Japanese authorities have faced the aftermath of the disaster with such efficiency, which the whole world has recognised."
The US Navy says more of its personnel are testing positive for low-level radiation, but its relief efforts will continue, Reuters reports.
And Iranian President Mahmoud Ahmedinejad has told Spain's RTE TV he does not forsee "any serious problem" at the Bushehr nuclear plant. "The security standards there are the standards of today," he said. "We have to take into account that the Japanese nuclear plants were built 40 years ago with the standards of yesterday."
Several countries who, like Japan, depend on nuclear power for much of their energy have insisted their facilities are safe. US Energy Secretary Steven Chu has said the US will learn from the disaster, but that plants in the country have "rigorous" safety rules.
China is organising a mass evacuation of its citizens from north-east Japan, the Associated Press reports. The Chinese embassy said it was sending buses to collect its nationals from Miyagi, Fukushima, Ibaraki and Iwate prefectures, "due to the seriousness of and uncertainty surrounding the accident at the Fukushima nuclear plant at present".
tweets: "Bullet Train services halted through Shizuoka due to 6.0M earthquake based there. Same one we felt here. There's my route to Shimane."
tweets: "Damn, another big earthquake, or two it seems. One in Yamanashi and one in Shizuoka. Felt it in Osaka."
Our correspondent says there are limited supplies in the town - people are only allowed to buy 10 litres of petrol at a time, and in some shops, only five items can be purchased by each customer. the authorities are attempting to repair major highways so deliveries can be brought through, he says.
The BBC's Clive Myrie in Yamagata says a man told him earlier today he was making his children shower every time they came home in an attempt to wash radiation from their skin. People are walking around wearing facemasks dipped in water in an attempt to filter the air, says our correspondent.
More on the US Army's radiation alert at the Yokosuka and Atsugi bases. In a statement, the Seventh Fleet said: "These measures are strictly precautionary in nature. We do not expect that any United States federal radiation exposure limits will be exceeded even if no precautionary measures are taken."
The BBC's Clive Myrie was in a hotel in Yamagata, in the quake zone, and described today's powerful aftershock. "I just sat there rooted to my seat, I didn't know what to do," he said. The tremor lasted only four or five seconds, but Friday's quake had lasted more than a minute. "I cannot begin to imagine what it was like for people in this country when that earthquake hit then, 14 minutes later, they were hit by a tsunami," said our correspondent.
AFP reports that several countries are screening passengers on flights arriving from Japan. But a spokesman for Lufthansa said no traces of radiation had been detected so far.
The US Army has recommended that personnel and families at the base - and at the Atsugi air base - take precautions, says Reuters.
The US military has detected low levels of radiation at its Yokosuka base, south of Tokyo, Reuters reports.
A reminder also that
a fake text message
claiming to be from the BBC has been circulating in Asia warning people of radiation leaks. This is nothing to do with the BBC so if you have received it, please ignore it and follow advice from your local authorities.
If you are just joining us, welcome to the BBC's live coverage of the aftermath of the devastating earthquake and tsunami in Japan. More than 2,400 people are now known to have been killed but many are still missing and whole towns have been swept away. There is deep concern about the safety of nuclear power plants close to the quake zone, with officials saying radiation from the damaged Fukushima Daiichi plant has reached harmful levels.
Reuters says a magnitude 6.0 tremor has struck - one of the largest of dozens of aftershocks felt in Japan over recent days. The agency says buildings in Tokyo were swaying.
Lauren Cha, a language teacher in Aizumisato Fukushima, writes: "Yesterday everything seemed fine and we were talked out of leaving, but today the situation looks a bit more grim and everyone is getting worried. The reports we are hearing from the international media sound sensational while the local media have been playing down the situation."
Levels of radiation in Tokyo spiked on Wednesday morning to around 20 times normal levels, according a spokesman for Tokyo's Metropolitan Government, quoted by the
. Shintaro Ishihara, said though raised they would not cause health problems.
Japan's largest utility may impose a rolling blackout in an upcoming three-day weekend and expects power demand to outstrip supplies on Wednesday, Tokyo Electric Power Co says according to Reuters.
Richard Robinson in Ashikaga, writes: "In response to David Littman's comment at 8:55GMT my school in Ashikaga was business as usual. The lights were kept off to save energy but all lessons went ahead as planned, even with sports being played outside."
Austria will relocate its Japanese embassy from Tokyo to Osaka given the unpredictable situation of the quake-hit nuclear power plants, the Austrian foreign ministry has said, according to Agence France Presse.
Eric Ouannes of Medecins Sans Frontieres
whose teams are helping with relief
tells the BBC World Service's Newshour Japan's aid efforts are "extraordinarly massive" and "pretty impressive".
Gerry Thomas, director of the
Chernobyl Tissue Bank
at London's Imperial College has told the BBC World Service that the advice that Japan has given to local residents - to keep doors and windows shut, and not hang washing outside is "exactly the right thing".
The US Federal Aviation Administration says it is prepared to re-route flights to Japan if the nuclear crisis there worsens, Reuters reports.
After a few hours of trading, European stocks have
over fears Japan's earthquake may undermine supply chains for global manufacturers.
We've just published a feature that gives a sense of the impact that the
are having on such a high-tech and nuclear power-dependent country.
Matthew, in Tokyo, writes: "I'm visiting a friend in Saitama (just outside Tokyo) tonight and learned that TEPCO had scheduled a blackout for this area between 6-10pm. It is now almost 9pm and the power has yet to go off, despite the local emergency announcement system having issued an alert."
The British government's chief scientist John Beddington says Japan's reaction to the nuclear crisis is entirely proportionate. He says the situation in Japan is "totally different" to Chernobyl.
France's nuclear safety authority says it classifies the Fukushima plant accident as level six. The maximum is level seven, used only once for the 1986 Chernobyl accident, Reuters reports.
German flag-carrier Lufthansa says it is diverting all Tokyo-bound flights to other Japanese cities until at least Sunday, Agence France Press reports.
Wondering what the world's press is writing about what this crisis means for the future of nuclear power? You'll find a
Mayu Iwakami, a resident of a suburb of Sendai, tells the BBC World Service that her and her family and neighbours are "try[ing] not to be in a state of hysteria until we actually get the information regarding radiation and a possible evacuation. Until then, we try to keep calm and carry on."
tweets: "I live in Fukushima. We need the truth. The information has been totally controlled "
The International Atomic Energy Agency says Japan has monitored 150 people for radiation levels and carried out decontamination measures on 23, Reuters reports.
Reuters is reporting that the US military says it has moved warships closer to the Japanese coast to aid with relief and rescue efforts
We've just published a story about the
fake text message
circulating warning people that radiation from the Fukushima nuclear plant has leaked beyond Japan.
Commentators are speculating about which countries are going to halt their nuclear power plans. Read more comment from across the web in the
The Fukushima International Association apparently offers a free English Information Service for Non-Japanese residents of Fukushima. They have
set up a page with information for people in
the area with guidance on such things as where the evacuation centres are, the plan for screening and so on.
tweets: "A few channels returning to local programming in #Tokyo, other stations have avoided commercials and broadcast public service spots instead."
Prime Minister Naoto Kan has strongly criticised the Tokyo Electric Power Company for its handling of the Fukushima No 1 nuclear plant, according to Japan's Kyodo news. "The TV reported an explosion. But nothing was said to the premier's office for about an hour," a Kyodo News reporter overheard Mr Kan saying during a meeting with company executives. "What the hell is going on?"
Germany's Foreign Minister Guido Westerwelle says that what we are witnessing in Japan is an "apocalypse". He says the international community must do everything it can to help Japan and adds it may shift Europe's approach to nuclear power: "After what happened in Japan it cannot be business as usual. This has consequences not only for Germany's energy policy but it will also have consequences for the international community's stance as well as the debate in Europe, and that's how we will now approach it."
Jack Edney in Chiyodaku, Tokyo writes: "Almost all of my friends here in the capital have left Tokyo with their families. They are scared about radiation reaching Tokyo and also many of their parents' companies are taking them either down south, or out of Japan altogether. School has been cancelled and it is all really slow here. I really do hope that I won't have to leave as well."
Russian Prime Minister Vladimir Putin has ordered Russia's nuclear agency to carry out a review of the future of the atomic energy sector in the country in the wake of the Japanese earthquake, AFP news agency reports.
The radiation dosages of up to 400 millisieverts per hour recorded at the Fukushima plant "are levels that you have to take very seriously indeed to ensure you avoid immediate health effects", Professor Richard Wakeford from the Dalton Nuclear Institute at the University of Manchester tells the BBC World Service. He says Japanese authorities will be imposing a ban on food and drink from the area and issuing iodine tablets to block the intake of radioactive iodine from the thyroid.
Some readers have been emailing the BBC about an "urgent" news flash purportedly from the BBC advising people in "Asian countries" to take certain steps in light of the radiation leak at the Fukushima plant in Japan, particularly if it is raining. Please be advised this is fraudulent and this advice has NOT been issued by the BBC.
Germany is moving to shut down its oldest nuclear reactors as Chancellor Angela Merkel convenes crisis talks on the future of atomic energy in light of events in Japan, Reuters said.
Francis Markus, a spokesman for the International Federation of Red Cross and Red Crescent Societies, says emergency workers in north-eastern Japan are still "very much focused on search and rescue and relief, with Japanese Red Cross medical teams dealing with hundreds of thousands of people in evacuation centres and these people people being provided with relief supplies of food, drinking water, blankets and other essentials".
The UN's weather agency says Japanese winds are dispersing radioactive material over the ocean, and there is no danger for Japan or the region for now, Reuters reports.
Andy Szymanski and Matt Alt, writing on Altjapan blog, say:
"This is a fluid situation, and an environmental disaster around the reactor site, but Tokyo residents and those outside of the evacuation zone do not seem to be in immediate danger as of this writing. The people in the most danger are the workers inside the plant. By exposing themselves to higher than normal radiation levels, they are sacrificing their health to keep the rest of us safe, and are the unsung heroes of this potential crisis."
The BBC's Piers Schofield
tweets: "very strong aftershock happening right now in yamagata - on 6th floor and wobbling bigtime."
John Stephenson in Mie writes: "I am 350 miles from the power plants and it seems like there are two Japans at the moment. At the supermarket today, if anything there seemed to be more food on the shelves than usual. It was quiet near the sea defences, as though people are staying away as a precaution. We have had utilities the whole time; for most of the country, nothing is wrong. If not for the TV pictures, we wouldn't know anything had happened. We are donating money but nevertheless there is a feeling of helplessness that we can't do more."
A Japanese nuclear safety official has confirmed reports that the water inside the waste fuel storage pool for the number 4 Fukushima reactor may be boiling, AP reports. Hidehiko Nishiyama refused to comment on the potential risks from the rising temperatures caused by a failure of cooling systems and said the plant's operator was considering what to do about theproblem.
James Durdey in Gyoda-shi, Saitama writes: "We are about 200km from the Fukushima plant and have decided to close our company this week. There is still a great deal of confusion regarding how serious this situation is. Power is expected to be cut off in around 10 minutes, and I am currently deciding if I should take my family away from this area. There are so many complications however, as there is limited fuel, and reduced transportation. We can only hope that the information we are being given is correct."
tweets: "Tokyo Metro has issued an advisory asking that people try to avoid travelling between 0730-0930 and 1800-2000. http://bit.ly/129jWy"
The Japanese earthquake may have very slightly shortened the length of a day - by about 1.8 microseconds, the US Geological Survey (USGS) says according to the Associated Press of Pakistan. It quotes the USGS as saying: "Earth's rotation changes all the time as a result of not only earthquakes, but also the much larger effects of changes in atmospheric winds and oceanic currents." It is nothing to worry about, it adds.
Martin Woodall in Saitama writes: "The train service from here to Tokyo is patchy and unreliable... Trains, buses and taxis to the International Airport, Narita are not running or again patchy. Also closer to the power stations! So, if a cloud was to come this way it is unlikely that we could get very far even if we wanted to... Therefore, we are going to stay put despite an urge to run, unless we are told to leave by the local government or bad news on your wonderful service."
Journalist Ulara Nakagawa
tweets: "Second stricken area in #Sendai we hit today was close to ocean and really obliterated. Hauntingly quiet too. Very very sad."
suggests in the Guardian
that "however horrifying the pictures, however moving the reports, there's a limit to how much suffering people can take on board - and it's extremely low". He adds that the bigger the number of fatalities, the harder it is for audiences to comprehend them.
London's benchmark FTSE 100 index slid more than 3% percent in morning trade to reach a 3.5-month low on fears about the financial cost of Japan's natural disaster and nuclear fallout, traders said according to AFP.
A spent nuclear fuel pool at Fukushima's number 4 reactor may be boiling and its water level falling, Kyodo news agency is reporting.
Japan's nuclear safety agency has said there are two holes of 8 sq m (86 sq feet) in a wall of the outer building of the number 4 reactor after an explosion there, Reuters reports.
University lecturer Adam Lebowitz in Tsukuba says: "According to the University of Tsukuba, as of 1300 there was no measurable change in the amount of radiation in this area. Until there is an official directive to evacuate the area I will stay put. The atmosphere is tense, attentive and watchful. Our utilities situation appears stable. We have water and gas. We were due to have rolling blackouts but have not had any so far. Our other concern is mainly food and fuel. As long as the highway is shut down shops cannot be restocked and the petrol stations remain empty. Agricultural products seem unaffected - vegetables and meat are still available."
suggests in Christian Science Monitor
that there may be a silver lining to the earthquake. He says the quake "accomplished what Japan's fiscal policy and central bank could not": rebuilding Japan will stimulate domestic growth.
The UK's Foreign Office has confirmed it has "severe concerns" about the whereabouts of a number of British citizens in Japan but is unwilling to give even an approximation of numbers at this stage, the BBC is told.
Tokyo Governor Shintaro Ishihara has been forced to apologise for a remark he made on Monday,
reports Kyodo News
. He apparently told reporters the tsunami was "divine punishment" for Japanese "egoism".
More than £400bn has now been wiped off the stock market value of Japan's bigger companies since the quake and tsunami hit on Friday, says the BBC's business editor Robert Peston. On one measure, Japanese shares have fall more over two days than since the crash of October 1987. Read more
in Robert's blog.
David Littman in Ashikaga, Tochigi writes: "The Japanese government are downplaying as well as being very selective with their information. I live 120km away from the power plant and all of the local schools have sent their students home. They have been instructed to stay indoors, and avoid skin exposure."
Official says rescuers have pulled a 70-year-old woman from the rubble four days after the tsunami, AP reports.
Amid reports that the wind direction at the Fukushima plant is turning inland, David Brenner, director of radiological research at Columbia University, tells the BBC World Service: "That would certainly impact on the amount of radiation exposure that individuals inland are getting. If one is thinking of Tokyo, it is a good distance away, and there's still going to be a great deal of dispersal of the radioactive plume before it gets that far... But this also depends on how much radioactivity is released from the reactors. " Those still working in the plant are now "at significant risk. In many ways they are already heroes... [they] are going to be suffering very high radiation exposures."
The WHO also says it has not received a request for help from Japan, but its radiation experts are on standby, Reuters says.
The World Health Organization in Geneva says Japan is taking the right public health measures to protect the population from radiation, says Reuters.
tweets: "Relatives are thinking about evacuating Tokyo. My wife, mother-in-law are staying put. We're over 60 and she said we don't have enough lifetime left to worry about this."
In the light of what's happening right now in Japan, countries like Indonesia are likely to come under increasing international scrutiny as they try to solve their energy needs by going nuclear, says the BBC's Kate McGeown in Jakarta. By 2025 Indonesia hopes to generate 4% of its power from nuclear energy. But the original proposal, to build a reactor in central Java, is now on hold after locals complained that it was near a faultline. Now there's a new plan off the coast of Sumatra - which is further from faultlines, but more expensive, as the electricity will have to be sent to the more populous island of Java through underwater cables.
The website Couchsurfing has
set up a page
for displaced people in Japan in need of a home to find temporary accommodation with those with a room/bed to spare. "Let's try to help the people of Japan as much as we can by opening our homes and our hearts to those in need!" it says.
The BBC's Ed Prendeville
tweets: "Seems there's concern on the streets of Tokyo about the increase in radiation, but people are still going about their business."
Time Out Tokyo
tweets: "The train schedules for Tokyo, as of 5pm (March 15), are here: http://bit.ly/eDSg3f."
After the sharp fall of Japanese shares Seijiro Takeshita of Mizuho Financial Group says analysts "were expecting a continuous drop, but not to this level. This is the third-deepest drop ever". He tells the BBC World Service that the "ambiguity" about events at the Fukushima plant "is exacerbating the situation. And at the same time there are worries about the procurement of electricity, particularly in the Kanto region, which is Tokyo. This is what really does the damage."
Ryan Barnes, from Nagoya writes: "I'm working through the Japan Exchange and Teaching (JET) Programme in Nagoya. Today was Sports Day at my school. Students played outside all day. People here seem tense, but on the surface, everything seems eerily normal."
Radiation levels at Fukushima nuclear power plant have fallen after an earlier sharp rise, the chief government spokesman says according to AFP.
Patrick Fuller who works for the Japanese Red Cross in the north-eastern fishing town of Otsuchi tells the BBC: "The place is utterly devastated, completely flattened apart from a few buildings. There's just twisted debris everywhere - and fires everywhere because a lot of the trawlers that went down spilled their fuel and gas bottles exploded in people's houses, so it's covered with smoke and fires. The civil defence are out there picking through the debris looking for survivors, but also removing dead bodies."
There has been a slight rise in temperature of two more reactors at Fukushima nuclear plant, the chief government spokesman says according to AFP.
Japan has told the IAEA it has extinguished a fire at the spent fuel storage pond of a reactor in Fukushima, Reuters says.
Denise Fukuda in Southern Tochigi writes: "The local supermarkets and convenience stores are working with dimmed lights to save electricity, and many of their shelves are empty (in Japan, empty shelves are normally unthinkable). In particular, everywhere seems to be out of bread, pot noodles, eggs, toilet paper, candles and batteries. This is partly due to people buying stuff in just in case, and partly due to factories etc., in the north being closed."
Simon Smith in Tokyo writes: "Just passed by the immigration centre here in Chiba - packed with over 400 people, many with suitcases queuing up for re-entry visas, eager to leave Japan."
The BBC's Nick Ravenscroft in Yamagata says even where he is - 1.5 hours from the coast, and 100km from the nuclear exclusion zone, relatively unaffected by the quake and tsunami - refugees have arrived from coastal areas on their journey to get to family and friends.
The BBC's Rachel Harvey says: "First phone signal for three days! Have left the area around Minimasanriku to look for petrol. Spent this morning in a hillside village where survivors are organising themselves into teams, building fires outside to boil water, storing supplies and sharing information about friends and relatives."
The BBC's Vivek Raj in northern Japan says people there are very concerned with the Japanese government finally admitting that radioactive leaks could affect public health.
Livy Bell in Kojimachi, Tokyo writes: "I think the Japanese government, amongst other nations, has absolutely failed in educating the public about nuclear power. Most of the population has no idea how nuclear power plants work, what safety measures are in place, what the radiation risks are and what practical implications these risks have. If they'd bothered to inform the public ahead of time, there wouldn't be this much panic."
tweets: "My local village of Ten'ei in Fukushima have asked everyone to avoid going out in the rain. We're about 100km away from the nuclear reactor."
Rock star Bryan Adams
tweets: "Calling all the great musicians and singers in the world, we should do a concert for Japan."
The threat from a nuclear reactor damaged by Japan's huge earthquake is judged "extremely high," AFP quotes France's foreign minister as saying as Japan met with other Group of Eight powers.
More on the fire at a spent fuel pond at Fukushima: It is at the number 4 reactor and "radioactivity is being released directly into the atmosphere", AFP quotes the IAEA as saying.
The BBC's Sally Eden stresses the destabilising effect of fears about the nuclear issue on the markets. At one point on Tuesday the Nikkei was down 14% - prompting trading to be restricted - before finishing down 11%.
Philip White, of the Citizens' Nuclear Information Center in Tokyo, tells the BBC he honours the courage of some 50 workers remaining in the nuclear plant, saying they are risking their lives by exposing themselves to what are conceivably very high doses of radiation. Says the authorities' unwillingness to listen to past advice about the dangers of quakes and tsunami has led to this situation, and they should have taken these well-founded critiques seriously.
EU energy chief Günther Oettinger has said Europe should consider whether it can meet its energy needs without nuclear power, Reuters reports.
There is a fire at a spent fuel pond of a reactor and radioactivity has been released into the atmosphere, says the IAEA according to AFP news agency.
Many flights to Japan have been cancelled. Taiwan's second carrier, Eva, is among the latest to announce it would cancel flights to Tokyo and Sapporo until the end of March, Reuters reports.
Peter Westaway - an economist at Japan's biggest investment bank, Nomura - has told BBC Radio 4's Today programme there are worries that the economic ramifications will be a lot worse than the 1995 Kobe earthquake, which saw a 1-1.5% fall in Japan's GDP. "The government will do everything that it can to put money into the reconstruction effort... But the big risk is that this has been a huge shock to the Japanese psyche. I think consumer sentiment is going to be very badly affected and that's another one of the big uncertainties hanging over this."
The Bank of Japan is pumping billions of dollars into the financial system. The bank made two cash injections on Tuesday, totalling $98bn (£61bn). This follows a record intervention yesterday, worth more than $180bn.
The fire at reactor 4 may have been caused by a hydrogen explosion, the IAEA says Japanese authorities have told it.
More than 1,000 people are dead or unaccounted for in Iwate prefecture, the Kyodo news agency is quoting police as saying.
Tokyo shares close down 10.55% as panicking investors dump stocks after the government said rising radiation levels at the Fukushima plant posed a threat to healt, the AFP reports.
Isao Araki, 63, an evacuee from Minami-soma, tells AP television: "Nuclear power is the most frightening thing, even more than a tsunami. The government, the ruling party, the administrators... nobody tells us, the citizens, what is really happening."
tweets: "The farm ministry says Japan has plenty of food, tells people there is no need for food hoarding."
An editorial in the New York Times
says that "the unfolding Japanese tragedy also should prompt Americans to closely study our own plans for coping with natural disasters and with potential nuclear plant accidents to make sure they are, indeed, strong enough. We've already seen how poor defences left New Orleans vulnerable to Hurricane Katrina and how industrial folly and hubris led to a devastating blowout and oil spill in the Gulf of Mexico".
Esther Waer, from Yamagata City, Japan, writes: "A friend just arrived from Fukushima City, had his radiation levels checked and all clear, he was 60km away. I really do not think the government are lying or covering up in anyway. The last thing we need is panic. "
tweets: "Thinking of the 50 workers on site at the Fukushima Power Plant risking their lives to bring the situation under control. THANK YOU."
Japanese PM Naoto Kan has sent a text message to mobile phones users across the country, asking them to conserve power, Reuters reports.
A no-fly zone is set for 30km-radius over the Fukushima nuclear plant, the Kyodo news agency is quoting ministry officials as saying.
Patrick Fuller, who works for the Red Cross in Japan's north-eastern fishing town of Otsuchi, tells the BBC's World Today programme that the situation there is dire: "Otsuchi is possibly the worst-affected town along the coastline, it was very close to the epicentre of the quake. People had very little time to escape the tsunami and half of the population possibly out of 17,000 people are unaccounted for still. People here are being incredibly stoic. It's hard to say what's going through their minds, when you talk to people they're very reserved, it's four days into this disaster and they are still in a state of shock.
Jeffrey Lilly, from Kawanehon, Japan, writes: "We're about 300 miles in a straight line from the Fukushima nuclear plants. My junior high school operates as normal, and kids at the elementary school next door play outside as I write this. No mention of the nuclear crisis whatsoever from any town officials. If not for the news I'd never know there was a problem. "
tweets: "Japan's biggest potential problem now, outside of plant vicinity, is not radiation but mass panic."
Thailand is to start doing random tests of imported Japanese food products for possible radiation contamination, the country's food and drug agency is quoted as saying by Reuters.
The European Commission is convening a meeting of energy ministers and nuclear experts in Brussels to assess nuclear safety issues in the wake of events in Japan.
However, a Tokyo government officials says the radiation levels in the city are not seen as harmful to human health, the AFP adds.
Higher than normal radiation levels are detected in Tokyo, the AFP is quoting the city government as saying.
Edward O'Brien, from Yotsukaido, Chiba-ken, Japan, writes: "Most of the people fleeing or complaining about information being withheld seem to be foreign residents. Very few Japanese people I know in Chiba and Tokyo are even thinking of evacuating."
The BBC's Chris Hogg in Tokyo says that Japan's nuclear safety agency says it suspects the explosion may have damaged the vessel that holds the number two reactor. That would make it a more serious incident than the two previous explosions at Fukushima that were thought just to have damaged the buildings that housed the reactors.
Air China, the country's flag carrier, has cancelled flights from Beijing and Shanghai to Tokyo
on Tuesday afternoon and in the evening.
A low level radioactive wind could reach Tokyo in 10 hours, Reuters is quoting the French embassy in the Japanese capital as saying.
Leke Ojumu, from Hakodate, Japan, writes: "Even though Hokkaido is around 400km away from Fukushima, the current situation with the nuclear power plants is a worry. Nevertheless, some of the foreign community around Hakodate are doing what we can to get together relief supplies for Fukushima/Miyagi. We weren't too badly affected up here so we've got to do what we can to help."
A fire which broke out Tuesday at Fukushima has now been extinguished, media reports say.
Helen Creak, who works for the Japan Exchange and Teaching (JET) programme in Yamagata prefecture, tells the BBC: "It is difficult to make rational decisions when we aren't getting honest and accurate information from the Japanese officials or news stations."
tweets: "Just passed Eneos gas station in Yamagata where line went for over 1 km, station attendant bring out portable battery charger for cars."
Japan's Chief Cabinet Secretary Yukio Edano says: "Now we are talking about levels that can impact human health. I would like all of you to embrace this information calmly. These are readings taken near the area where we believe that the release of radioactive substances is occurring. The further away you get from the power plant or reactor the value should go down".
Winds over the stricken nuclear plant are blowing slowly towards the Kanto region, which includes Tokyo, Reuters reports.
Radiation is 400 times the annual legal limit near Fukushima's reactor 3, the Kyodo news agency reports.
Apologies for the delay with updating - this was due to technical problems.
And Mr Kan also confirms earlier reports that a fire has broken out at Fukushima's reactor 4.
The premier also urges people within 19 miles (30km) of the Fukushima complex in the area "to remain indoors".
Addressing the nation, Prime Minister Naoto Kan says that "there is a high risk of futher radioactive material coming out".
The official death toll from the earthquake and tsunami rises to 2,414, Japanese police say. But officials fear that at least 10,000 may have died.
tweets: "Japan waiting for (PM) Kan. NHK said it would be "message to nation", rather than news conference".
An article in the
Japan Times newspaper
says: "So far, the response to Friday's earthquake and tsunami has been better than the 1995 Hanshin-Awaji earthquake thanks to better official communications between Tokyo bureaucrats and politicians and local governments, and also the existence of the Internet and social media."
Mark Kemp is working as an English teacher in Fukushima province. He lives about 75 miles (121km) from the nuclear plant. He tells the BBC that the news about the latest explosion is very worrying: "The more that goes wrong at the plant, the less 120 kilometres really feels. When I was around town yesterday, everyone I saw seemed tense. They seemed to trying to be getting on with their lives. But there was a definite tension in the air. You could definitely feel it."
Radiation is feared to have leaked after the container vessel was damaged at Fukushima's reactor 2, the Kyodo news agency is quoting Tokyo Electric Power Company as saying.
The Bank of Japan offers to pump 5tn yen ($61bn) into the financial system to try to soothe money markets shaken by the earthquake and tsunami.
The official death toll from the earthquake and tsunami has topped 2,400, the AFP news agency is quoting police as saying.
Details are now emberging about radiation levels after the blast at Fukushima's reactor 2 at 0610 local time (2110 GMT Monday). Tokyo Electric officials say that one hour of exposure at the nuclear plant would be equivalent to eight times at what a person might experience naturally during the year.
Welcome to the fifth day of our live coverage of Japan's earthquake disaster. Stay with us for the latest updates - reports from our correspondents on the ground, expert analysis, and your reaction from around the world. You can contact us via email, text or twitter. We'll publish what we can.