A magnitude 6.9 earthquake today killed about 400 people in the mountainous Tibetan Plateau in southwest China and left more than 10,000 injured as houses, schools and offices collapsed.
A series of quakes and aftershocks caused low, mud-brick buildings in Qinghai Province's ethnically Tibetan Yushu county to collapse, residents and state media said.
Troops have been dispatched to the area and some aid shipments from private organisations have set off from the provincial capital, Xining.
"People are very scared," said Pierre Deve, with Snowland Service Group, a local non-government organisation, adding that many had already given up hope for those still trapped.
The Tibetan plateau is regularly shaken by earthquakes, but casualties are usually minimal because so few people live there.
Many residents of the remote area could be left without shelter in temperatures that hover near freezing in Yushu and even colder in mountain villages. Five thousand tents and 100,000 thick, cotton coats and heavy blankets were being sent to help survivors cope with strong winds and near-freezing temperatures, the Qinghai provincial government said in a statement.
Government officials told state media the majority of houses had been badly damaged.
State television showed footage of paramilitary police using shovels to dig around a house with a collapsed wooden roof. A local military official, Shi Huajie, told state broadcaster CCTV rescuers were working with limited equipment.
"The difficulty we face is that we don't have any excavators. Many of the people have been buried and our soldiers are trying to pull them out with human labor," Mr Shi said. "It is very difficult to save people with our bare hands."
The Japanese government has also offered emergency aid, Japan's government spokesman Hirofumi Hirano said. "The response was that there was no need at this stage," he told reporters.
Xinhua reported that the early morning quake had caused some schools and part of a government office building to cave in. Some vocational school students and primary school students were trapped in the rubble, it said, although residents said most students had been able to flee to playgrounds.
The widespread collapse of school buildings when other surrounding buildings stayed standing, caused anger and accusations of corruption after the devastating May 2008 earthquake in Sichuan Province, which killed 80,000.
"A lot of one-storey houses have collapsed. Taller buildings have held up, but there are big cracks in them," resident Talen Tashi said.
People from the Yushu prefecture highway department were frantically trying to dig out colleagues trapped in a collapsed building, department official Ji Guodong said.
The quake was centered in the mountains that divide Qinghai province from the Tibet Autonomous Region. The foothills to the south and east of the area are home to herders and Tibetan monasteries of Yushu county, while the area to the north and west is arid and desolate.
The quake was centred 240km north northwest of Qamdo in Tibet and 375km south southeast of the mining town of Golmud in Qinghai, and had a depth of 10km, the United States Geological Service said.
A magnitude 5.0 quake struck the same region late last night, and large aftershocks rattled the town this morning, sending fearful residents into the streets.
Agencies