China quake kills thousands in one county.

A powerful earthquake struck central China on Monday and state media reported that as many as 5,000 people were killed in a single county while nearly 900 students were trapped after their school collapsed.

Nearly 900 students in southwest China's Sichuan Province were feared buried when a high school building collapsed here in an earthquake measuring 7.8 on the Richter scale on Monday afternoon.

At least four third-graders -- two boys and two girls -- were confirmed dead at Juyuan Middle School in Juyuan Township of Dujiangyan City, about 100 kilometers from the epicenter in Wenchuan County, parents and witnesses said.

Xinhua reporters saw a three-story school building had partially collapsed. Some buried teenagers were struggling to break loose from underneath the ruins while others were crying out for help.

The official Xinhua News Agency said 3,000 to 5,000 people had died in Beichuan county in Sichuan province after the 7.8-magnitude quake. Another 10,000 people there were believed to be hurt.

Desperate efforts are under way to find survivors.

The earthquake struck at 2:28 pm (0628 GMT) in Wenchuan county, Sichuan province, and could be felt in cities hundreds of kilometres away, including Beijing, Shanghai, Hong Kong and Bangkok.

The epicenter of the quake was located at 31.0 degrees north latitude and 103.4 degrees east longitude, the bureau said.

A statement issued by the local government in Aba prefecture, where the epicentre was located, said buildings had cracked and collapsed, and mountain roads were damaged.

The area has a population of about 110,000 residents, the state-run Xinhua news agency reported.

Wen Jiaboa, China's prime minister, has announced that he will visit the affected areas. He has also ordered for troop deployment to carry out rescue and relief.