Thousands killed in China earthquake

Beijing: China said on Tuesday at least 18,645 people were buried under debris in the town of Mianyang, the epicentre of the earthquake.

The death toll has jumped to more than 12,000 a disaster relief official said, although only 3,629 people have been confirmed dead.

The first group of rescuers reached Sichuan on Tuesday, and 1,300 rescue teams and troops were seen pulling out other bodies, many badly battered, from the rubble of one collapsed building.

A strong aftershock was also felt in China's Chengdu, sending office workers out on the streets nearly 24 hours after the disaster struck.

Prime Minister Wen Jiabao warned the situation in the quake zone was severe as China mobilised its 2.3 million-strong armed forces to spearhead the search and rescue effort.

President Hu Jintao urged an "all-out" effort to rescue victims and the authorities announced an initial allocation of $29 million of relief funds.

The 7.9 magnitude earthquake also trapped hundreds of students under the rubble of schools and caused a toxic chemical leak in one of the worst quakes in decades.

In Beichuan province, just east of the epicentre, 80 per cent of the buildings had collapsed and some 10,000 people were injured aside from 3,000 to 5,000 dead, Xinhua said.

Media reported a chemical plant in Shifang city cratered, burying hundreds of people and spilling more than 80 tons of toxic liquid ammonia from the site.

In Juyuan town in Duj-iangyan city, just south of the epicentre, a school collapsed, burying about 900 students and immediately killing four ninth graders, Xinhua reported.

Xinhua said its reporters in Juyuan town saw buried teenagers struggling to break free from the rubble "while others were crying out for help."

The quake emptied office buildings across the country in Beijing; could be felt as far away as Vietnam; crashed telephone networks, and hours later left parts of Chengdu, a city of 10 million, in darkness.