BEIJING—An earthquake with a magnitude of 7.5 struck China's Sichuan province on Monday, less than 100 km (60 miles) from the provincial capital of Chengdu.
The quake was felt across much of China and as far southwest as Bangkok, Thailand's capital, some 3,300 km (2050 miles) away, where office buildings swayed for several minutes.
Chengdu a fast-growing metropolis of 10 million people and home to the Giant Panda Breeding Research Base is around 1,300 km (2070 miles) southwest of Beijing.
"All the buildings are swaying back and forth," said a university student in the central city of Wuhan, adding that people had rushed outside and one single-storey building had collapsed.
"We felt continuous shaking for about two or three minutes," said another office worker. "All the people in our office are rushing downstairs. We're still feeling slight tremblings."
China's tallest building, the Jinmao Tower in Shanghai, as well as other highrise buildings were ordered evacuated after the quake and aftershocks.
Many workers poured from their buildings in Bejing's financial centre, but there were no visible signs of damage. The subway system was unaffected.
The U.S. Geological Survey said on its website (http://earthquake.usgs.gov) that the quake struck at 0628 GMT at a depth of 29 km (18 miles). The agency originally put the strength of the quake at 7.8.
Japan's meteorological agency said no warnings for a tsunami has been issued.
Sources said there was no immediate impact to the Three Gorges Dam project, the weight of whose massive reservoir, hundreds of kms from Chengdu, experts have said could increase the risk of tremors.
A source at the biggest refinery in western China, Lanzhou, said the plant also appeared unaffected by the quake.
An official with the Sichuan provincial seismic bureau said the epicentre of the quake was in Wenchuan county, in the Aba Tibetan and Qiang Autonomous Prefecture, a mountainous area populated mostly by Han Chinese but with sizeable Qiang and Tibetan populations.
On Chinese state television, a reporter said that telephone calls to Wenchuan were not connecting. State TV also said the government was preparing to send rescue and aid teams to the region.
A receptionist at the Tibet Hotel in Chengdu said the hotel had evacuated its guests, but said things were "calm" there now. "It was very sudden and I am not sure what has happened elsewhere, but we are OK here," the receptionist said.
The quake was felt as far away as Vietnam and Thailand, startling office workers in high-rise buildings.
"We have a number of reports that high buildings along Sukhumvit and Sathorn roads (in Bangkok) felt the tremors, but there are no reports of damage," a geologist at Thailand's Meteorological Department told Reuters.
High-rise residential and office towers in the western suburbs of Vietnam's capital, Hanoi also shook for several seconds, witnesses said, but there was no visible damage. Hundreds of residents and office workers left the buildings as a precaution.