Aid teams are battling chaos to reach thousands who survived sea surges triggered by a massive earthquake in the Indian Ocean. BBC correspondents report from affected areas around the region and beyond.
Friday 31 December
Dumeetha Luthra: Galle, Sri Lanka: 1726 GMT
There is only one way of moving around Hamba Tota now and that is picking your way through the rubble, the rubble that was once homes, shops, a school, a mosque.
The trees that are still standing are colourfully adorned, but these aren't decorations. These are people's clothes.
On the ground, a children's school bag, garishly out of place in the midst of these ruins. Everyone has a story to tell, a story of loss and desperation.
Travelling by helicopter gives a perspective on the magnitude of this disaster.
Mile upon mile, the coastline is ravaged. It is not just that homes are destroyed, it is everything is destroyed. The crops are ruined with saltwater. The fishing boats are submerged in the sand. People's livelihoods have quite simply been drowned.
Lars Bevanger: Oslo, Norway: 1617 GMT
People from the Nordic countries are among the foreign tourists hardest hit by the catastrophe with more than 4,000 Swedes, Norwegians, Danes and Finnish still missing.
There is no sense of celebration here this New Year's Eve.
People are focusing on the plane loads of injured and shocked tourists which are still arriving from Thailand and on newspaper front pages carrying pictures of the missing and there are many of them.
Most of the Nordic missing were on holiday in southern Thailand, the most popular resort for escaping the dark and cold winters here.
Many local authorities in all the Nordic countries have cancelled New Year celebrations. The money saved will be given to aid organisations.
The bishop of Oslo earlier called on people to light a candle in remembrance of the tsunami victims rather than set off the customary fireworks.
Churches will stay open throughout the holiday weekend.
In nations like these with small populations, few are left untouched by the tragedy and there is a real sense of loss all around. Swedish Prime Minister Göran Persson called this the most dramatic catastrophe in that nation's history.
Charles Haviland: Nagapattinam, India: 1535 GMT
The centre of Nagapattinam Town still presents a shocking scene.
On a low-lying island, corpses can be seen while a number of funeral pyres smoulder.
Bleach, intended to prevent the spread of infections, continues to be scattered along the streets.
Some people are sitting in it by the ruins of their homes.
Dominic Hughes: Phuket, Thailand: 1528 GMT
A candle-lit ceremony to mourn the dead marked the beginning of a sombre new year. Emotions were raw, many were in tears.
It was all in marked contrast to the usual scenes here at this time of year. Holidaymakers would usually be getting ready to party through the night.
But it is hard to celebrate when you're surrounded by the death and destruction wrought by the Indian Ocean tsunami.
Most tourists have left the holiday island, but some have not. Of those who remain, many have volunteered in hospitals and helping with the clear up.
Although most Thais would save their celebrations for Chinese new year in February, 31 December is usually a fairly riotous evening in Phuket.
But this year the government has cancelled all official celebrations and many hotels and bars are using their parties to raise funds for relief efforts.
The new year will be ushered in without the usual fanfare.
Geeta Pandey: Port Blair, India: 1509 GMT
Authorities in the islands of Andaman and Nicobar say they have information that all the indigenous tribals are safe.
Vice-Admiral Arun Kumar Singh said a team of officials had returned after visiting the area where the Sentinelese live.
The Sentinelese, who number only 100, are known to be a hostile group and they do not allow outsiders to enter their habitat.
The vice-admiral said all the other tribal groups, including the Jarawas, Onges, Shompen and Holchu, are also safe and there have been no casualties.
Jeremy Bowen: Mullaitivu, Sri Lanka: 1445 GMT
Sri Lanka's Tamil Tiger rebels say that more than 3,000 people died in the northern town of Mullaitivu out of a population of more than 5,000. Buildings on the beach were completely flattened by the waves. There is almost nothing left standing.
Tamil Tiger leaders here have organised groups of young rebels to pick up most of the bodies, which are rotting badly. They are locating corpses by smell and burning them on the spot.
We went at least one mile (1.6km) inland where we saw people taking bodies out of a paddy field, lining them up and then burning them. By Thursday evening the sky above Mullaitivu was black with the smoke of funeral pyres.
The local Roman Catholic priest, Father Anansha Kumar, told me that 95% of the people in this area were Catholics. "Isn't it a shame they are not getting Christian burials?" I asked.
Reflecting on the fears for public health he replied: "I don't think the Lord is very fussy about this."
Jonathan Head : Banda Aceh, Indonesia: 1415 GMT
Water is the most critical problem here. The entire water supply has been contaminated - you can't imagine how they could clean it up as the number of bodies is just overwhelming.
I've just come from Thailand where it was pretty shocking but nothing compares to the health problems presented here by the thousands and thousands of bodies and the inability of the authorities and the survivors to deal with it. They are digging mass graves now but the number littered around is just staggering.
The entire town - where it hasn't been levelled - is covered in a sea of filthy mud with bodies and bits of rubble stuck in it. I think the authorities are going to have to think about moving people out because it's just uninhabitable.
There aren't the resources to clean up a mess this staggeringly big - the place looks as though a giant has picked it up, shaken it, torn it to pieces and then thrown this layer of mud, rubble and bodies across it.
All the people I've spoken to here say there is no more Banda Aceh. They're packing their bags and leaving whatever way they can.
Chris Hogg : Phuket, Thailand: 1350 GMT
The New Year celebrations in Thailand, although not as big as those held to mark the Chinese New Year in a few weeks time are traditionally boisterous affairs.
This year, across the country they've been cancelled, or toned down. An end of year party in Bangkok featuring celebrities and politicians that was expected to attract tens of thousands of people has been shelved on the orders of the Prime Minister.
Many of the hotels or bars that are still holding events are using them to try to raise money for the victims of the disaster.
Broadcasters on local TV channels are wearing black. Flags fly at half mast.
Candlelit vigils have already been held in Phuket and some of the other worst affected areas. Saturday will be a day of mourning.
Rachel Harvey : Banda Aceh, Indonesia: 1215 GMT
More flights are arriving in Aceh all the time but still it's not enough.
The United Nations is warning that up to half a million people may be living without shelter, safe water or sufficient food.
Many of them still haven't received any help at all since the earthquake struck on Sunday. It's simply been impossible to reach them.
In the central square of Banda Aceh, mechanical diggers are hard at work clearing away at the debris. But in the side streets local people are trying to do the job by hand.
At Friday prayers across the province the thousands who perished were remembered. One Muslim leader broke down in tears as he tried to deliver his sermon.
"The Acehnese people must try to pick themselves up again," he said. "We're weeping now, but we can't afford to grieve for long. We have to start rebuilding our lives."
Chris Hogg : Phuket, Thailand: 1115 GMT
The reality is that a lot of Thai people in this region are still very scared. Some of them are still living up in the hills - they've gone up to high land and they don't want to return home.
The authorities are trying to distribute aid to them and also mosquito nets and sprays because they're worried about the spread of malaria in such rough country.
Gina Wilkinson : Galle, Sri Lanka: 1025 GMT
People have been burying their dead without registering them with the authorities.
Part of the reason for that is the most severely affected part of Sri Lanka is along the east coast where there are lots of Muslim villages. Customs there dictate that the dead should be buried within 24 hours so a lot of people have been buried already.
The authorities say that because of this, they may never get a clear picture of how many people died in Sri Lanka in the tsunami.
But today, on this day of mourning, people are coming together from all religions for multi-faith services to remember the dead and also to pray for the estimated one million people who have been affected by this disaster.
Rachel Harvey : Banda Aceh, Indonesia: 1010 GMT
Some aid is now beginning to come through but it's clearly not enough.
International aid agencies have this huge logistical problem - even if they get the aid this far they've got to be able to distribute it and keep it safe in warehouses - but there aren't safe warehouses as most of the buildings have been damaged or destroyed.
There's a lack of fuel and blocked roads. Some areas are still only accessible by air or by ship.
Charles Haviland : Nagapattinam, southern coast, India : 0830 GMT
Individual volunteers got in to the camps for displaced people with basic supplies of food and blankets after defying police attempts to turn them back because of the government warning of a possible new tidal wave.
The advice to evacuate has now been called off, but it played havoc with the relief operations which are still desperately needed here.
One man said he was nearly trampled under foot getting into the town to try and save his family as others were fleeing.
But in many places aid distribution is getting back to normal and many of those who left their homes have returned. But the need for clean water and basic shelter for people who have lost their homes here is still overwhelming.
Rachel Harvey : Banda Aceh, Indonesia: 0612 GMT
It's Friday prayers in Banda Aceh. The small mosque in the compound of the governor's residence is one of the few buildings that's been left unscathed by Sunday's earthquake and tsunami.
The local government officials and the military chiefs - the people that are co-ordinating the relief operation here - have taken time out to pray.
Almost everybody inside the mosque has lost someone - a friend, a relative, a colleague - and this is their moment to reflect and to grieve.
Gina Wilkinson : Galle, Sri Lanka: 0527 GMT
This is a day when Sri Lankans will honour their dead in multi-faith services that will bring together Buddhist, Hindu, Christian and Muslim communities. They will also be praying for the hundreds of thousands of people who survived the tsunamis but have been left with nothing.
A government spokesman says lorries of aid are arriving in all but a few of the worst-hit areas, which are still only accessible by helicopter or boat.
The spokesman says most tsunami victims now have access to at least some food, clean water and medicine with thousands of tonnes of foreign aid already in the country, but he says sheltering the half-a-million people whose homes have been destroyed remains a major challenge.
The government says it will not allow the displaced to rebuild homes constructed illegally on parts of the devastated coastline and whole communities will need to be relocated.
Chris Hogg : Phuket, Thailand: 0515 GMT
It is going to be a long and difficult struggle to identify the foreigners who were killed here.
The experts brought in to help the Thai authorities say it is now virtually impossible to identify the bodies by sight. Instead, they will try to use dental records or to match DNA samples provided by the relatives of those who are missing.
Ten international teams of forensic scientists are now involved in the operation, led by the Australians. They have warned that people who travel to Thailand to try to find the bodies of their loved ones could end up getting in the way.
They are urging people to provide DNA samples and information about their relatives' dental records to the authorities in their home countries instead.
Geeta Pandey : Port Blair, Andaman Islands: 0310 GMT
The police chief in the Andaman and Nicobar Islands has said it will be safe to assume that most of those reported missing are dead.
The inspector-general of police, Shamsher Bahadur Deol, told the BBC that some of these people may still be in the jungle and some of them are still returning. But he said that number is getting fewer and fewer by the day and the signs are not encouraging at all.
Officials say up to 10,000 people are missing or dead, and many say even that is a conservative estimate.
Mr Deol says it may never be known accurately as to how many people perished here since only 400 bodies have been recovered so far.
Authorities say the low body count could be because a large number of bodies are lying in the forest and it is difficult to reach them because of stagnant water and sludge.
Also they say tsunamis usually pull the bodies into the bottom of the ocean and most of these will probably never be found.
Rachel Harvey : Banda Aceh, Indonesia : 0200 GMT
Tens of thousands of people are internally displaced, are sleeping rough without proper shelter or sanitation. There is an acute shortage of fresh drinking water and food is running low.
Everybody that has lived through this and survived is now effectively at some kind of risk.
This is a story that has emerged very slowly. The news coming out of Sri Lanka and other parts of the region was much quicker.
But access to Aceh was always very difficult because of the ongoing conflict between the Indonesian government and separatist rebels.
We didn't hear very much from here at all and we thought this was because... no one was hear to tell us, in terms of journalists.
But then slowly it emerged that the reason we were not hearing anything was because of the extent of the damage.
Slowly, each day we are hearing new horrific stories.
Just in the town of Banda Aceh here, I keep beginning to think I've got my head round this. I keep beginning to think I understand how bad this is now, just in this one town.
Then you turn another corner, see something else horrific and think - no, actually I still really haven't, this is absolutely cataclysmic.
It's crucial to try and remember that we are here to do a job.