A total of 7651 people have died in China's Sichuan province after a powerful earthquake struck there on Monday, the official Xinhua news agency said, citing government officials.

The news agency said the figure had been established by a disaster relief headquarters set up by Chinese Premier Premier Wen Jiabao, who referred to the quake as a "major disaster."

Casualties were also reported in other provinces close to Sichuan, state media said.

The quake, with a magnitude of 7.8, struck close to densely-populated areas of Sichuan province including the capital Chengdu.

It swayed buildings in Beijing and Shanghai and was also felt in Hong Kong, Hanoi and Taipei, residents said, and even in the Thai capital Bangkok, 1800 kilometres from the epicentre.

A major disaster

Chinese Premier Wen Jiabao called it a "major disaster" and urged calm.

"Facing disaster, the most important thing is calm, confidence, courage and strong leadership," Wen told China's CCTV television on a flight to the heart of the quake-hit zone.

"We will definitely overcome this major disaster".

China's state-run Xinhua news agency cited local disaster relief officials saying 3000 to 5000 people were estimated to have died in just one district of Sichuan, Beichuan County.

A further 10 000 people were injured in the county, where officials said 80 percent of buildings had collapsed.

Students feared buried

Xinhua earlier reported up to 900 students were feared buried when a high school collapsed in Dujiangyan, northwest of Chengdu.

At least four children were confirmed dead there, Xinhua said, and a local official in the city said "rows of houses" had been demolished.

Another four children died and more than 100 were injured when two primary schools crumbled in the sprawling metropolis of Chongqing.

President Hu Jintao urged an "all-out" effort to rescue victims. Military troops were ordered to help with the disaster relief work.

The international airport at Chengdu was closed and air traffic disrupted elsewhere.

Damage to Olympic venues?

An Olympic spokesperson said none of the 31 venues for the Beijing Olympics in the capital and other host cities had been damaged.

"They are earthquake proof to a high degree and no damage was done," said Sun Weide, deputy director of the Olympic media and communications office.

The civil affairs ministry, cited by Xinhua before the estimate toll from Beichuan County, said that as at 6pm (10am GMT), 107 people were confirmed dead and 34 injured in Sichuan and neighbouring Gansu and Yunnan provinces.

The quake struck 93 kilometres from Chengdu, a city of more than 12 million people, and some 260 kilometres from Chongqing and its 30 million.

The State Seismological Bureau located its epicentre in Wenchuan County, a mountainous region home to the Wolong Nature Reserve, China's leading research and breeding base for endangered giant pandas.

Xinhua quoted an official saying the landmark Three Gorges Dam in Sichuan province had not been affected.

However, buildings shook in Beijing and Shanghai, residents reported, with many people evacuating tower blocks and rushing onto the street. There were no immediate reports of damage there.

Both the Chinese seismological bureau and the US Geological Survey, which use different scales, measured it at 7.8.

The quake struck shortly before 2.30 pm (6.30am GMT), according to the USGS, at a depth of just 10 kilometres.

A series of aftershocks continued to rock the region, including one of 5.8 near Chengdu measured by the USGS.

The phone network there and elsewhere around the country appeared to suffer a meltdown as people tried to find out what happened.

Two residents near downtown Chengdu whom AFP contacted by phone said they felt a violent shaking that tossed glassware to the floor and toppled street lights.

The quake was felt in the Taiwanese capital Taipei, where buildings swayed for half a minute, and in the southern Chinese territory of Hong Kong.

In Hanoi, residents said some high buildings shook for around five minutes but there were no reports of damage.

The catastrophic 1976 quake

One of the biggest quakes ever recorded was in China in 1976, which killed 242 000 people.

That quake, centred in the northern city of Tangshan, lasted for 15 seconds and flattened 90 percent of buildings. The death toll, out of a population of one million, made it one of the world's deadliest in the 20th century.

In 1920 and again in 1927, separate quakes in northwestern China each left some 200 000 dead.

AFP