19 000 buried under rubble

China's most devastating earthquake in three decades killed more than 12 000 people with the toll likely to soar after state media said on Tuesday nearly 19 000 were buried under rubble in one city alone.

Storms were hampering rescue efforts in the mountainous area around the epicentre of Monday's 7.9 magnitude quake that pummelled the southwestern province of Sichuan.

State media reported scenes of devastation as a small contingent of officials arrived in villages near the epicentre at Wenchuan, a remote county cut off by landslides about 100 km northwest of provincial capital Chengdu.

In Yingxiu, a town of 12 000 people, only 2 000 had been found alive, state television quoted He Biao, an official, as saying.

"They could hear people under the debris calling for help, but no one could, because there were no professional rescue teams," He said. About 60 000 people were unaccounted for.

Medicine

"What we most need is medicine. There is no medicine, there are no doctors and after such a long time, no food," He said.

More than 12 000 people have died in Sichuan and more than 26 000 were injured, according to vice governor Li Chengyun. More than 3.46 million "rooms" had been damaged.

Another 18 645 people were also buried under debris in the city of Mianyang, neighbouring Wenchuan, Xinhua news agency said, suggesting the death toll was likely to rise sharply.

Thousands were reported buried under factories, schools and other buildings elsewhere. Hundreds more have died in neighbouring provinces.

He said several reservoirs upstream of the Min river, a major Yangtze river tributary flowing through the quake-hit region, were "in a very dangerous status and the dams may burst". Officials have also warned more powerful aftershocks could hit the region and mudslides could wreak a greater toll.

Aftershock

A strong aftershock rocked Chengdu on Tuesday, one of 2 354 in the province over the past day, unnerving residents.

More than 50 000 troops had joined disaster relief efforts or were advancing to the area. Thousands had been ordered to parachute into Wenchuan, where rain and thick clouds had prevented military helicopters from landing.

Premier Wen Jiabao, visiting Sichuan, ordered troops to clear roads to Wenchuan. "Please speed up the shipping of food. The kids have nothing to eat now," Wen said amid a crowd of crying children.

In Dujiangyan - about midway between Chengdu and the epicentre - there was devastation, with buildings reduced to rubble and bodies in the streets.

About 900 teenagers were buried under a collapsed three-storey school building, as frantic relatives tried to push past a line of soldiers, desperate for news of their children.

Wen bowed three times in grief before some of the first 50 bodies pulled out, Xinhua reported. "Not one minute can be wasted," said Wen, a trained geologist.

British tourists missing

A group of 19 British tourists were missing near the epicentre, their travel company said on Tuesday.

The group, on a Travel Collection tour, were travelling with a guide by coach from Chengdu to Wolong, home to a large panda reserve. Phone lines to the area are cut.

China said that there had been no reports of foreign casualties as of midday.