China's most devastating earthquake in three decades killed at least 8,533 people in western Sichuan province and over 250 in neighboring provinces on Monday and razed 80 percent of the buildings in one county, initial estimates said.
The 7.8 magnitude quake struck in the middle of the school day, toppling several schools in the region, trapping many hundreds, media reports said.
Rescuers were still cut off from the epicentre in Wenchuan, a county of 112,000 people about 100 km (62 miles) from the Sichuan provincial capital Chengdu, Xinhua said. The death toll was expected to rise significantly.
More than 7,000 of the dead were in Sichuan's Beichuan Qiang Autonomous County, where 80 percent of the buildings were destroyed, according to media reports.
"We are doing everything we can, but the roads are blanketed with rocks and boulders," Xinhua quoted Sichuan deputy party chief Li Chongxi as saying.
Most phone lines in Wenchuan were down and a website for the region's Aba prefecture said the quake had cut several major highways and communications were largely severed in 11 counties.
"The road started swaying as I was driving. Rocks fell from the mountains, with dust darkening the sky over the valley," a driver for Sichuan's seismological bureau was quoted by Xinhua as saying near the epicentre.
Beichuan, part of Sichuan's Mianyang city about 160 km from capital Chengdu, has a population of 161,000, meaning about one in 10 residents were killed or injured.
About 900 teenagers were buried in the rubble of a collapsed three-storey school building in the Sichuan city of Dujiangyan.
Local villagers had helped dozens of students out of the ruins and cranes were excavating the site as parents looked on, Xinhua said.
Crying for Help
"Some buried teenagers were struggling to break loose from underneath the ruins while others were crying out for help," the agency said.
Hundreds of people were trapped under collapsed schools, factories and dormitories in Shifang in Sichuan, Xinhua said, including several hundred trapped under two collapsed chemical plants.
Some 80 tonnes of highly corrosive liquid ammonia had leaked in Shifang forcing the evacuation of 6,000 people, it said.
Hundreds of people were buried under rubble in a collapsed hospital in Dujiangyan.
Troops had begun pouring into the region with sniffer dogs, life detection equipment, and some firefighters carrying explosives to blow up rocks piled on the roads, the national television said.
Landslides had cut off three major rail lines leading to Chengdu, stranding 31 passenger trains and 149 cargo trains, Xinhua said, but no casualties had been reported.
The National Tourism Administration had ordered travel agencies to halt tour groups to or through the quake area.
Felt in Bangkok
The earthquake's force was enough to cause buildings to sway across China and as far away as the Thai capital Bangkok.
The US Geological Survey said on its website (http://earthquake.usgs.gov) the main quake struck at 0628 GMT at a depth of 10 km (6 miles).
Thousands of people were milling about in the main square of Chengdu late on Monday, where at least 45 had died and 600 were injured, state television reported.
Premier Wen Jiabao arrived in Chengdu and President Hu Jintao ordered an all-out rescue effort, Xinhua reported.
In Washington, President George W. Bush said the United States was ready to help.
"I extend my condolences to those injured and to the families of the victims of today's earthquake. I am particularly saddened by the number of students and children affected by this tragedy. The United States stands ready to help in any way possible," Bush said in a statement.
Some 85 people have been confirmed killed in northern Shaanxi, 48 in northwestern Gansu, 50 in Chongqing municipality, and one in Yunnan province, Xinhua said, citing the national headquarters of disaster relief.
