A magnitude 7.5 earthquake struck western China on Monday, shaking buildings as far away as Thailand and Vietnam, witnesses and geologists said. Thousands of people were evacuated from buildings in Beijing, some 900 miles from the epicenter.

The quake struck 60 miles northwest of the Sichhuan provincial capital of Chengdu at 2:28 p.m., the U.S. Geological Survey said on its Web site. It said the quake was centered 6.2 miles below the surface.

Calls to emergency response numbers in Chengdu rang busy. A resident reached by phone in Chengdu said people flooded from buildings, but there was no sign of damage or injuries.

The area where the quake hit lies on the eastern edge of the Tibetan plateau where mountains rise sharply and the population density is generally thin.

In the Chinese capital Beijing, about 930 miles away, buildings swayed for more than two minutes but there were no immediate reports of damage or injuries.

Thousands of frightened office workers and shoppers evacuated buildings, including offices of the organizing committee for the Beijing Olympics. People lingered outside buildings in the central business district even a half-hour after the shaking stopped.

A magnitude 7.5 earthquake is considered a major event, capable of causing widespread damage and injuries in populated areas.

In the Taiwanese capital of Taipei, 100 miles off the southeastern Chinese coast, buildings swayed when the quake hit. There were no immediate reports of injuries or damage.

The quake was felt as far away as the Vietnamese capital of Hanoi, where some people hurried out of swaying office buildings and into the streets. A building in the Thai capital of Bangkok also was evacuated after the quake was felt there.