BEIJING (Reuters) - China prepared to tackle more unrest in its ethnic Tibetan enclaves on Monday, after crushing Lhasa protests against Chinese rule in which Tibet’s exiled representatives say as many as 80 people were killed.

Lhasa, the capital of the remote Himalayan region, was under tight police watch, but reports and officials said demonstrations by ethnic Tibetans flared in at least two Chinese provinces, widening the worries of the Communist authorities.

“We are completely capable of protecting the security of the Tibet people. Right now the overall situation in Tibet is very good,” the mayor of Lhasa, Doje Cezhug, said from Beijing, in remarks posted on the Tibet government’s Web site.

But protests hit ethnic Tibetan areas in the Chinese provinces of Sichuan and Gansu on Sunday, reducing the chances of an early end to the instability that is a major challenge to China’s leaders just months before it hosts the Olympic Games.

In the Sichuan county town of Aba, a police officer said a crowd of Tibetans had hurled petrol bombs and burned down a police station and a market.

In Gansu’s Machu town, a crowd of 300-400 carried pictures of Tibet’s exiled spiritual leader, the Dalai Lama, and shouted slogans as they marched on government buildings, breaking windows and doors and setting fire to Chinese shops and businesses, the Free Tibet Campaign said.

The London-based group said 100 Tibetan students staged a sit-in at Northwest Minority University in Gansu’s capital, Lanzhou, a worry for a country with a history of student unrest, notably the Tiananmen Square protests of 1989 that ended in a military crackdown.

In Lhasa, the situation was quiet but tense and police locked down the region as a midnight deadline loomed for protesters to give themselves up to the police.

The government advised foreign tourists to leave and confirmed it had stopped granting foreigners tourist permits.

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Western governments have called for restraint in China’s response to the violent protests, and Chinese official media tried to defend the security measures used in quelling them.

“Throughout the incident, Lhasa police officers exercised great restraint. They remained patient, professional and were instructed not to use force,” Xinhua news agency said.

The Dalai Lama, who has lived in India since 1959, the year of a failed uprising against Chinese rule in Tibet, called for an investigation into what he called cultural genocide. Chinese troops entered Tibet in 1950 after the Communists took power in Beijing.

A Nobel peace prize winner, the Dalai Lama is revered in the Tibetan community but reviled as a traitor in China, where authorities stepped up the rhetoric against him.

Xinhua quoted Tibetan officials as saying the Dalai Lama’s charge was “downright nonsense” and trumpeted its development policies in the region.

Critics say those policies helped fuel the protesters’ anger by favoring Han Chinese migrants to the region, contributing to a huge wealth gap between Chinese and Tibetans.