The Dalai Lama yesterday called for an investigation into China's tough response to protests in Tibet, and whether it was deliberate "cultural genocide".

The comments from Tibet's spiritual leader came as police and troops locked down Lhasa, the capital of Tibet, two days after street protests against Chinese rule that the region's government-in-exile said had killed 80 people.

"Whether the Chinese government admits or not, there is a problem. The problem is the nation with ancient cultural heritage is actually facing serious dangers," he told a news conference at his base of Dharamsala in northern India. "Whether intentionally or unintentionally, somewhere cultural genocide is taking place," he said, adding that he wanted an investigation into the clashes.

The Dalai Lama, saying he felt "helpless", added that the international community had the "moral responsibility" to remind China to be a good host for the Olympic Games. "So now we really need miracle power," he told a conference often interspersed with laughter from the exiled Tibetan leader.

The International Olympic Committee yesterday called for a peaceful resolution to the unrest in the Himalayan region of Tibet, which threatens to derail China's hopes for a smooth run-up to the Beijing Olympic Games. The street protests in recent days look set to overshadow the build-up to the August 8-24 Games, which China was hoping would be a display of the country's unity and prosperity.

"The International Olympic Committee (IOC) shares the world's desire for a peaceful resolution to the tensions of past days in the Tibetan region of China," said IOC spokesman Giselle Davies. "We hope that calm can return to the region as quickly as possible."

The Olympic movement is no stranger to calls for boycotts of its four-yearly summer showpiece. China's policy on Sudan and the war-torn region of Darfur have already brought calls from activists for athletes to stay away from Beijing.

Hollywood actor Richard Gere, chairman of the International Campaign for Tibet, said on Friday that his personal view was that it would be "unconscionable" to attend the Beijing Games if China failed to deal peacefully with the unrest in Tibet.

But yesterday, the Dalai Lama said the Games should not be called off, even if the international community had a "moral responsibility" to remind China to be a good host.

China has ruled Tibet since its troops marched in to take control in 1950.

About 200 Tibetan protesters hurled petrol bombs, burning down a police station, a market and houses in a county in southwest China yesterday, a police officer said.

The demonstrators also torched two police cars and a fire truck in Aba county, Sichuan, one of four provinces with large Tibetan populations bordering the Himalayan region of Tibet.

Security forces fired tear gas to disperse the crowd and arrested five people, including two women, the police said. About 100 paramilitary policemen were mobilised to guard the main government building.

A flurry of protests against Communist rule erupted last week in Tibet's capital, Lhasa, and in Chinese provinces populated by pockets of Tibetans - the biggest in the region in nearly two decades.

Monks first took to the streets of Tibet last Monday to mark the 49th anniversary of an earlier uprising, and protests soon spread to adjoining regions inhabited by pockets of Tibetans.

China has said at least 10 "innocent civilians" died, mostly in fires lit by rioters in Lhasa on Friday.

China has declared a "people's war" of security and propaganda against support for the Dalai Lama, the spiritual leader of Tibetan Buddhists, underlining that it will not heed calls from around the globe for a lenient response to the riots.

The Tibetan Centre for Human Rights and Democracy said monks from the Amdo Ngaba Kirti monastery, also in the Aba prefecture, raised the banned Tibetan flag and shouted pro-independence slogans after their morning prayer session yesterday morning.

Chinese security forces stormed the monastery, fired tear gas and prevented the monks from taking to the streets, the centre said in an e-mail. The monastery houses about 2,800 monks.