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 epicenter of Monday's 7.9 magnitude quake that pummeled the southwestern province of Sichuan.
State media reported scenes of devastation as a small contingent of officials arrived in villages near the epicenter at Wenchuan, a remote county cut off by landslides about 100 km (60 miles) northwest of provincial capital Chengdu.
In Yingxiu, a town of 12,000 people, only 2,000 had been found alive, state television quoted official He Biao 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.
"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, neighboring 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 neighboring provinces.
The vice governor 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.
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 epicenter — there was devastation, with buildings reduced to rubble and bodies in the streets. Many residents simply stood beside their wrecked homes, cradling possessions in their arms. Others huddled in relief tents under heavy rain. (See more on the quake in the video at left.)
Rescuers had worked through the night, pulling bodies from buildings demolished by the quake, which rolled from Sichuan across much of China and was felt as far away as Bangkok and Hanoi.
About 900 teenagers were buried under a collapsed three-story 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.
"We're still pulling out people alive, but many, many have died," said one medical worker.
A group of 19 British tourists were missing near the epicenter, 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.
The Sichuan quake is the worst to hit China since the 1976 Tangshan tremor in northeastern China where up to 300,000 died.
China's benchmark stock index ended down on Tuesday and trading in the shares of 66 companies was suspended.
Analysts said they did not expect a major economic impact from the disaster, but that supply shortages could fuel inflation, already at a near 12-year high.
The State Administration of Grain ordered local governments to ensure grain and cooking oil supplies and price stability.
China's largest life insurer, China Life, said it expected claims for the quake to far exceed those for freak snowstorms that hit the country early this year.
Bloggers wondered about the quality of construction and why so many school buildings were reduced to rubble.
Offers of aid have come from around the world. The United States, Britain, Japan, the European Union, South Korea and Taiwan have offered assistance since the disaster, which occurred three months before the Beijing Olympics.
Olympic officials assured foreigners planning to visit China for the Games that the country was safe.
A minute's silence would start each stop of the domestic torch relay and celebrations would be scaled down.
The International Olympic Committee said it would donate $1 million and the United Nations also offered support.