BEIJING - TWO earthquakes jolted the capital of Tibet and surrounding areas, killing at least nine people and collapsinghundreds of houses, China's state news agency said on Tuesday. Rescuers rushed in to try to save people buried in the rubble.

The US Geological Survey said on Monday's first quake measured magnitude 6.6 and struck at 4.30pm (4.30am Singapore time) 80 kilometres west of Lhasa, more than 2,600km from Beijing.

The second temblor measuring magnitude 5.1 hit about 15 minutes later, some 96km west of the Tibetan capital, it said.

Earlier reports from China's official Xinhua News Agency said at least 30 people died, but the agency revised the death toll to nine on Tuesday, saying the previous figure was inaccurate as it came from 'unauthoritative sources' and required verification.

Hundreds of houses collapsed in Gedar township near the epicentre in Dangxiong County, and traffic and telecommunications were cut.

Nineteen people were injured, Xinhua said, citing Hao Peng, deputy chairman of the Tibetan regional government.

An unknown number of people were trapped, and soldiers and rescue workers were dispatched to the site, Xinhua said. Deaths also were reported in a neighbouring county, Xinhua said, but no figures were available.

The Lhasa airport and the Qinghai-Tibet railway - which stretches from western Qinghai province to Tibet - continued to operate, the agency said.

China's State Seismological Bureau said the initial temblor was centred in Dangxiong county, which has a population of about 42,000 people, mostly herdsmen.

In Lhasa, employees at the Civil Affairs Bureau rushed out of their building when the tremors began but returned soon after, said an official who refused to give her name.

Xinhua said that so far, none of the city's landmarks, such as the Potala Palace, appeared to be damaged.

One of the agency's reporters in Lhasa said shops remained open and there was no panic on the streets.

China's far west is fairly earthquake-prone. On Sunday, a magnitude-5.7 earthquake shook the Xinjiang region, which borders Tibet, Tajikistan and Kyrgyzstan, which also suffered a 6.6-magnitude quake hours later. At least 60 people were killed when a village collapsed.

A 7.9 magnitude earthquake on May 12 devastated parts of Sichuan province, just east of Tibet, killing 70,000 people and leaving 5 million homeless. -- AP