A powerful earthquake with a magnitude of 7.6 has hit Kashmir, the territory disputed by India and Pakistan since independence from Britain in 1947.
More than 1,000 people are thought to have died, with reports of casualties still coming in.
BBC correspondents in the region report on the impact of the earthquake.
Barbara Plett: Islamabad, Pakistan : 1927GMT
Rescue workers here continued in driving rain as night fell, still trying to pull survivors out of a 10-storey apartment block that had collapsed into rubble.
In north-western Pakistan, the death toll climbed steadily. In particularly distressing news, local police officials said hundreds of children died when at least one school was destroyed.
But the worst-hit area was Pakistan-administered Kashmir. In the regional capital, Muzaffarabad, many buildings collapsed, including a courthouse. However an army spokesman said most of the damage was in mountainous areas where houses are made of mud bricks. He said whole villages had vanished.
Prime Minister Shaukat Aziz has now called for international aid.
Barbara Plett: Islamabad, Pakistan : 1625GMT
In Islamabad rescue workers are still trying to dig people out of the ruins of a collapsed apartment block. But even in this relatively well-serviced pocket of the capital, they are finding it hard to cope.
People say the operation is unorganised and there isn't proper equipment. And the challenge is greater further north in Pakistan-administered Kashmir - the epicentre of the earthquake.
Many houses in the mountains are made of mud. An army spokesman said villages had collapsed and towns had vanished. Army helicopters are needed to reach the afflicted. Roads have been blocked by mudslides. Telephone lines are down.
This is the test President Musharraf has set his forces, but as they face one of Pakistan's worst natural disasters, it is not clear if they can meet it.
Zaffar Abbas : near Muzaffarabad, Pakistan-administered Kashmir : 1615GMT
We have now made three attempts to go to Muzaffarabad from three different directions but have failed. All roads have been blocked by landslides. There are trees and big rocks on the road and its impossible to approach Muzaffarabad from any direction. We will soon be turning back but the situation is getting desperate.
Thousands of people have descended from the villages that have been virtually destroyed. They want to go to Muzaffarabad to take their injured to the city where there are medical facilities and hospitals but they have no way of approaching the city, or any other town for that matter.
Navdip Dhariwhal : Delhi, India : 1502GMT
The quake's impact was felt across India. In Punjab, shops and houses collapsed and rescuers worked their way through rubble to find survivors. Its intensity was felt as far south as the capital Delhi, causing damage to buildings. And as far away as Gujarat, the tremors triggered widespread panic.
But the worst affected parts were the mountain towns bordering the Pakistani side of Kashmir. Stone and mud houses in remote villages were reduced to rubble. Many other homes were buried under landslides triggered by the quake. In one town it's feared two hundred people died but the casualties could be far greater.
The line dividing the two sides of Kashmir is heavily militarised. The Indian army too suffered casualties and the air force was brought in to help the rescue effort.
Zaffar Abbas : near Muzaffarabad, Pakistan-administered Kashmir : 1426GMT
The initial part of the journey from Islamabad was pretty smooth - there were little signs of any real damage.
The minute we became close to the city of Muzaffarabad the damage was evident. There were landslides all over the place, rocks on the road, a number of houses were damaged and relief work was going on mainly by the local villagers.
Where I'm standing now, about 20 kilometres from the city of Muzaffarabad, there's a huge landslide blocking the entire road. Hundreds of villagers are trying to clear the road but it looks like it may take them the whole night to get the job done. So from this end, the Pakistan-administered Kashmiri area is completely cut off from the rest of the country.
Barbara Plett : Islamabad, Pakistan : 1340GMT
It's difficult to get around in the affected areas in Pakistan-administered Kashmir. Landslides have blocked roads between Islamabad and the regional capital Muzaffarabad, so people can't bring in supplies. People also can't find out what's going on because the telephone lines are down, too.
The army has been put into commission - Pakistan has a military government so it's quite easy to deploy quickly. They have a crisis response unit and that has geared into action - sending helicopters with medical teams and the facilities to set up medical camps and over time, I suppose, bring in supplies to help people get their lives back together. But this isn't a team that has been trained specifically to deal with earthquake disasters.
Altaf Hussain : Srinagar, Indian-administered Kashmir : 1310GMT
The authorities say about 200 people have been killed across the state. Thousands of houses have been damaged and 400 tents have been sent to the worst-affected areas. The Indian air force has been helping to evacuate the those who have been injured. The authorities say it's still to early to tell the exact magnitude of the damage as communication is difficult.
Altaf Hussain : Srinagar, Indian-administered Kashmir : 1212GMT
The epicentre of the earthquake has been found in Pakistan-administered Kashmir, west of its capital, Muzaffarabad. Thousands of houses have been damaged, mostly in the border districts of Baramullah, Kupwara and Poonch.
A fire broke out in a market in the border town of Uri after the earthquake. Almost all the shops have been damaged. The state's chief secretary told a press conference that relief work has begun in all the affected areas.
The army has also joined in the rescue operation. Hospitals have been geared up for receiving casualties and doctors on leave have been asked to resume duty immediately.
The administration is working overtime to restore essential supplies such as electricity and water, disrupted by the earthquake.
Hospitals have received hundreds of trauma cases. Many people are still staying out of their homes, fearing more tremors.
Rahimullah Yusufzai : Peshawar, Pakistan : 1158GMT
The first shock was very serious, we were all rocked and the whole place was shaking. I ran out of my home.
It continued for almost six minutes, it was very long. Since the first shock we have had a dozen after-shocks.
We keep coming back to our houses and then having to flee again. Some have decided not to return to their homes for now.
Barbara Plett : Islamabad, Pakistan : 1123GMT
There was a tremor here in the last few minutes. The roof, where I was standing, felt like it was rolling beneath me. But it was a small aftershock.
Driving around the streets in the past hour, it is calm here in the city, but the streets are empty.
Many thought Islamabad was earthquake-proof, but that wasn't so, as an apartment block collapsed. If it caused that damage here, imagine what it did to homes made of mud in the remote villages.
I think we will be hearing some very sad tales from those areas very soon.
Altaf Hussain : Srinagar, Indian-administered Kashmir : 1111GMT
The numbers of deaths have been rising and now it is estimated at around 200. Thousands of houses are damaged, some destroyed, leaving some people homeless.
Four hundred tents have arrived in Uri, but this is an insufficient number of tents, more are needed. Some field hospitals have been set up too.
I'm told the Red Cross teams have now reached all the affected areas in Indian-administered Kashmir.
The army has offered full support.
The road to Tandgar was blocked by a massive landslide, but that has been cleared. There is no water supply in some areas, but engineers are now working to restore that.
There was another tremor here about 15 minutes ago, which caused some panic.
Rahimullah Yusufzai : Peshawar, Pakistan : 1056GMT
Military spokesman Major General Shaukat Sultan told journalists that more than 1,000 people are feared killed.
He said Pakistan-administered Kashmir and the North-West Frontier Province, which borders Afghanistan, were the worst-hit.
A senior police officer in Peshawar, the capital of the North-West Frontier province, told the BBC that initial reports put the number of those dead at 140.
In Baramulla, Kashmiri women and children weep following the quake
The operational police head, Malik Saad, said the toll would go up once information from the remote areas trickles in.
He said more than 100 people were killed in the northern district of Battagram after a their houses collapsed in the tremors.
He said another 19 were killed in Mansehra district, 10 in Kohistan, six in Shangla, four in Abbottabad and one in Swat.
The officer said the Balakot town of Mansehra has been severely hit. The earthquake was followed by several aftershocks.
Officials said the quake epicentre was 250km north of Peshawar in the Hindu Kush mountains. The seismological centre in Peshawar recorded its magnitude at 7.6.
In some places, the collapse of school buildings killed and injured students.
Fear of another earthquake was widespread in the wake of the eight aftershocks that rocked Peshawar and other places. Police and hospital sources said more than 250 injured people had been brought to hospitals from across the province, and more were being shifted there for medical treatment.
Altaf Hussain : Srinagar, Indian-administered Kashmir : 1042GMT
Latest reports from the border district tell us that 200 have died in that area.
As of now, the Indian government have promised full help to the area, and at the moment there has been no request for international help. But the picture is not clear yet.
Some people are on the roadside, with no facilities, no food, awaiting aid. In other parts of the state, life is going on as usual.
Barbara Plett : Islamabad, Pakistan : 1023GMT
The earthquake struck early in the morning, centred in the mountains of Pakistan-administered Kashmir. It was difficult to get a clear picture of the damage because telephone lines were down. But Pakistani officials said buildings collapsed in the region's capital, Muzaffarabad.
The interior minister, Aftab Sherpao, spoke of entire villages being wiped out. The army has mobilised its crisis-response teams. It sent medical aid in by helicopter because roads have been blocked by landslides.
The earthquake also left its mark further south. In one town, a school came down and in Pakistan's capital, Islamabad, part of an apartment block was reduced to rubble. Rescue workers are still trying to dig out people trapped beneath large stone slabs, and stretchers carry away bloodied survivors.
Seismic activity is common in the volatile Hindu Kush mountains, but this is the strongest earthquake felt here in many years.
Altaf Hussain : Srinagar, Indian-administered Kashmir : 1009GMT
I now understand that 172 people have died in Indian-administered Kashmir, 157 civilians and 15 soldiers.
The reports say that there are more than 600 people injured. In Uri, it is believed that 104 people are dead. The authorities are running 500 tents to the area.
Army facilities have also been badly hit, which has a big knock-on effect on the rescue operation.
Nick Bryant : Delhi : 1002GMT
We did feel the tremors here in Delhi, but we are 965km (600m) away. I was on the ground floor and felt it shake. Those on higher floors would have found it very frightening.
Uri, on the road that links the divided territory, is badly damaged. I understand 70% of the buildings there have experienced some sort of structural damage.
It is a heavily militarised area and we understand some soldiers have been killed too.
Information is difficult to get at the moment, some of these areas are quite remote and communication is difficult in normal times.
Altaf Hussain : Srinagar, Indian-administered Kashmir : 0956GMT
The Met office in Srinagar says the epicentre of the earthquake has been found in Pakistan-administered Kashmir, west of its capital, Muzaffarabad.
Thousands of houses in Indian-administered Jammu and Kashmir have been damaged. The civil administration has asked the army's main hospital in Srinagar to receive casualties.
The earthquake hit at 0925 local time. People ran out of their homes into open spaces, with women and children crying in panic. Hospitals have received hundreds of trauma cases.
Many people are still staying out of their homes fearing more tremors. Most of the government offices and educational institutions have been closed.
Waliur Rahman : Dhaka, Bangladesh : 0947GMT
The earthquake that struck the South Asian subcontinent has also jolted parts of Bangladesh. The earthquake caused widespread panic among residents at various cities and towns, but there was no immediate report of casualties or damage from anywhere of the country.
According to the Earthquake Observation Centre in the south-eastern port city of Chittagong, the earthquake was of a magnitude of 5.4 and it was felt just before 1000 local time and lasted for about a minute.
Zaffar Abbas : Islamabad : 0925GMT
The Pakistani army have emergency teams and they are working now, moving towards the badly effected villages.
They have sent several helicopters with medical aid to the areas involved and they are hoping to bring in more helicopters from other cities.
Kashmir and the Pakistan northern region are badly hit. There are road blocks caused by landslides, which are hampering access by road. The telephone lines have come down too. It will be a while before we have a clear picture of the damage.
Early indications are that the devastation has been big and widespread.
Altaf Hussain : Srinagar, Indian-administered Kashmir : 0855GMT
Officials in Indian-administered Kashmir say at least 60 people have died so far in the earthquake. They said of these 45 were civilians and 15 were army soldiers.
Altaf Hussain : Srinagar : 0840GMT
It appears the town of Uri, near the Line of Control [between Indian- and Pakistani-controlled Kashmir], seems to have suffered the most damage. An army spokesman said 60-70% of the buildings in Uri have been damaged.
The main Uri market was engulfed in a major fire following the earthquake. Though the fire has been brought under control, it caused extensive damage to the shops.
Altaf Hussain : Srinagar, Indian-administered Kashmir : 0803GMT
Police in Indian-administered Jammu and Kashmir say at least 22 people have been killed and hundreds injured after a powerful earthquake hit the state on Saturday morning.
Five people are buried under the debris of a house.
The earthquake hit at 0925 local time. People ran out of their homes into open spaces with women and children crying in panic.
Many people are still staying out of their homes fearing more tremors.
Barbara Plett : Margala Towers, Islamabad, Pakistan : 0620GMT
There are desperate rescue efforts going on here. A number of floors of the apartment block collapsed and in front of me is a small hill of broken concrete over which and under which rescue workers are desperately trying to dig out survivors.
A number of casualties have already been carried out on stretchers, but there are more underneath the rubble.
Everyone is pitching in - official rescue workers, but also people who live here and those ordinary people who've just come to help.
Zaffar Abbas : Islamabad, Pakistan : 0527GMT
The big jolts in Islamabad and all its neighbouring towns and villages started around 0830 local time (0330 GMT).
Within minutes, reports had started to come in from places as far as Lahore, Quetta, Peshawar and Kashmir, of a major earthquake.
Millions of panic-stricken people came out in the open as the tremors continued for nearly three minutes.
Initial reports suggest there have been landslides in several places in the country's north and north-west region and in Pakistan-administered Kashmir.
A number of villages in the mountainous area have been wiped out and road links have been cut from some of the towns and villages in northern Pakistan.
Barbara Plett : Islamabad, Pakistan : 0520GMT
I'm at a building called the Margala Towers in Islamabad. Part of it has collapsed and I'm looking at a small hill of concrete that people are running across frantically.
At the moment, straight ahead of me, there's a sort of cavity that people have gathered around. They're trying to pull survivors out and things are getting a bit frantic.
They've also brought up a water pipe that's gone up over the hill of concrete and they've been throwing up bottles of water - presumably to hand to those people who are stranded, either caught underneath the rubble or stranded in their apartment buildings.