A magnitude 6.9 earthquake on Wednesday killed about 300 people in the mountainous Tibetan Plateau in southwest China and left more than 8,000 injured as houses, schools and offices collapsed.

A series of quakes and aftershocks caused low, brick buildings in Qinghai Province's ethnically Tibetan Yushu county to collapse, residents and state media said. Troops have been dispatched to the area.

About 300 had been killed in the county seat, also known as Jyeku, state television said, citing the deputy secretary-general of the Yushu government, Huang Limin.

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 the high mountain villages. Government officials told state media the majority of houses had been badly damaged.

'I see injured people everywhere. The biggest problem now is that we lack tents, we lack medical equipment, medicine and medical workers,' Zhuohuaxia, a local spokesman, told the Xinhua news agency.

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 students at some schools had been able to flee to the 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 people.

'A lot of one-storey houses have collapsed. Taller buildings have held up, but there are big cracks in them,' resident Talen Tashi told Reuters.

People from the Yushu prefecture highway department were frantically trying to dig out colleagues trapped in a collapsed building, department official Ji Guodong said by telephone.

'The homes are built with thick walls and are strong, but if they collapsed they could hurt many people inside,' Zhuo De told Reuters by phone from the capital of Qinghai province after contacting his family in Yushu.

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 150 miles (240 km) north northwest of Qamdo in Tibet and 235 miles (375 km) south southeast of the mining town of Golmud in Qinghai, and had a depth of 6.2 miles (10 km), the United States Geological Service said.

A magnitude 5.0 quake struck the same region late on Tuesday night, and aftershocks of magnitude-6 and over rattled the town Wednesday morning, sending fearful residents into the streets. – Reuters