Beijing, April 14 (IANS) About 400 people were killed Wednesday when a devastating earthquake jolted northwest China's Qinghai province, bringing down buildings like a pack of cards and leaving thousands bloodied and shaken.

The 7.1 magnitude quake struck the Yushu prefecture at 7.49 a.m. at a depth of 33 km. Eighteen aftershocks quickly followed, causing widespread destruction.

About 400 people have died and many are buried under tonnes of debris of collapsed houses in Gyegu town near the epicentre in Yushu, Xinhua quoted local official Huang Limin as saying.

The strong quake toppled houses, temples, gas stations and electric poles, triggered landslides, damaged roads, cut power supplies and disrupted telecommunications.

A reservoir cracked and workers frantically tried to prevent the outflow of water.

Gyegu town, with a population of about 100,000, was in shock.

About 700 soldiers tried desperately to clear away the rubble and rescue the buried people while over 5,000 additional rescuers, including soldiers and medical workers, have been dispatched to the quake-hit region.

"Our top priority is to save students. Schools are always places that have many people," said Kang Zifu, an army officer.

More than 85 percent of the houses in Gyegu had collapsed, said another official Zhuohuaxia who added that "the streets in Gyegu are thronged with panic, injured people, with many bleeding from the head.

"Many students are buried under the debris due to building collapse at a vocational school.

"I can see injured people everywhere. The biggest problem now is that we lack tents, we lack medical equipment, medicine and medical workers," the desperate man said.

Educational institutions suffered extensive damage.

"I do not know how many students have died. I recovered several bodies from the debris," said Zhu Liang, a rescuer at the Yushu vocational school.

Chang, a teacher at Yushu Primary School, a boarding school with about 1,000 students, said: "Buildings in our school were all toppled, and five pupils have died.

"Morning sessions did not begin when the quake happened. Some pupils ran out of dorms alive, and those who had not escaped in time were buried," Chang said.

Shi Huajie, a police officer, said that students of some primary schools were among the buried.

"We have to mainly rely on our hands to clear away the debris as we have no large excavating machines. We have no medical equipment, either."

Although Yushu is a sparsely-populated region, experts said the quake was very likely to cause "heavy" casualties.

"The strong quake has a shallow depth and the epicentre is close to the prefecture seat," said Sun Shihong of the China Earthquake Networks Center.

"It is estimated there will be heavy casualties, as the quake occurred in the early morning and most of the local residents were yet to get up."

The quake was strongly felt in the neighbouring Qamdo Prefecture and other regions in Tibet.

Two aircraft were used to ferry rescuers and relief supplies.

"Aftershocks above 6 magnitude are still likely to happen in the coming several days," warned Liu Jie, also of the China Earthquake Networks Center.