BEIJING — China ordered tourists out of Tibet's capital Saturday while troops on foot and in armored vehicles patrolled the streets and enforced a strict curfew, a day after riots that a Tibetan exile group said left at least 30 protesters dead.

The protests against Chinese rule of Tibet that began Monday are the largest and most violent in the region in nearly two decades. They have spread to other areas of China as well as neighboring Nepal and India among other countries.

China's governor in Tibet vowed to punish the rioters, while law enforcement authorities urged protesters to turn themselves in by Tuesday or face unspecified punishment.

The unrest began on the anniversary of a 1959 uprising against Chinese rule of Tibet. Over the centuries, Tibet was at times part of China's dynastic empires. Communist forces invaded the region in 1950 to reclaim the Himalayan region and seize the commanding heights overlooking rival India.

The protests began with 300 monks demanding the release of other monks detained last fall. But political demands soon came to the fore.

Violence erupted Friday after police tried to stop monks from protesting in central Lhasa and ordinary Tibetans vented pent-up anger on Chinese, hurling stones and torching shops and cars. Witnesses said they heard gunshots on Friday and more shooting on Saturday night.

The violence comes just two weeks before China's Olympic celebrations kick off with the start of the torch relay, which passes through Tibet. China is gambling that its crackdown will not bring an international outcry over human rights violations that could lead to boycotts of the Olympics.

Beijing's hosting of the Olympics in August has already brought scrutiny of China's human rights record and its pollution problems. But so far, the international community has reacted to the crackdown in Tibet only by calling for Chinese restraint without any threats of an Olympic boycott or other sanctions.

"We believe that the boycott doesn't solve anything," International Olympic Committee President Jacques Rogge told reporters Saturday on the Caribbean island of St. Kitts. "On the contrary. It is penalizing innocent athletes and it is stopping the organization from something that definitely is worthwhile organizing."

Streets in Lhasa were mostly empty Saturday as a curfew remained in place, witnesses said.

Tourists reached by phone or those who arrived Saturday in Nepal described soldiers standing in lines sealing off streets where there was rioting Friday. Armored vehicles and trucks ferrying soldiers were seen on the streets.

"There are military blockades blocking off whole portions of the city, and the entire city is basically closed down," said a 23-year-old Western student who arrived in Lhasa on Saturday. "All the restaurants are closed, all the hotels are closed."

One foreigner in Lhasa said Chinese troops armed with automatic rifles had set up positions in the old city after clearing it of people and were firing at anything that moved.

Plooij Frans, a Dutch tourist who left the capital Saturday morning by plane and arrived in the Nepali capital of Katmandu, said he saw about 140 trucks of soldiers drive into the city within 24 hours.

"They came down on Tibetan people really hard," said Frans, who said his group could not return to their hotel Friday and had to stay near the airport. "Every corner there were tanks. It would have been impossible to hold any protest today."

Government workers in Lhasa said Chinese authorities have been prevented from leaving their buildings.

"We've been here since yesterday. No one has been allowed to leave or come in," said a woman who works for Lhasa's Work Safety Bureau, located near the Potala Palace, the former residence of the Dalai Lama. "Armored vehicles have been driving past," she said. "Men wearing camouflage uniforms and holding batons are patrolling the streets.

Tourists were told to stay in their hotels and make plans to leave, but government staff were required to work.

Some shops were closed, said a woman who answered the telephone at the Lhasa Hotel.

"There's no conflict today. The streets look pretty quiet," said the woman who refused to give her name for fear of retribution.

Xinhua reported Saturday that Lhasa was calm, with little traffic on the roads.

"Burned cars, motorcycles and bicycles remained scattered on the main streets, and the air is tinged with smoke," the report said.

China's official Xinhua News Agency reported at least 10 were killed Friday when demonstrators rampaged in Lhasa, setting fire to shops and cars.

"The victims are all innocent civilians, and they have been burnt to death," Xinhua quoted an official with the regional government as saying.

Twelve police were also injured, Xinhua reported.

The Dalai Lama's exiled Tibetan government in India said it had confirmed Chinese authorities killed at least 30 Tibetan protesters but added the toll could be as high as 100. There was no confirmation of the death toll from Chinese officials and the numbers could not be independently verified.

China maintains rigid control over Tibet, foreigners need special travel permits to get there and journalists rarely get access except under highly controlled circumstances.

In the western province of Gansu, police fired tear gas Saturday to disperse Buddhist monks and others staging a second day of protests in sympathy with anti-Chinese demonstrations in Lhasa, local residents said.

In the western Chinese province of Gansu, several hundred monks marched out of historic Labrang monastery and into the town of Xiahe in the morning, gathering hundreds of other Tibetans with them as they went, residents said.

The crowd attacked government buildings, smashing windows in the county police headquarters, before police fired tear gas to put an end to the protest, residents said. A London-based Tibetan activist group, Free Tibet Campaign, said 20 people were arrested, citing unidentified sources in Xiahe.

"Many windows in shops and houses were smashed," said an employee at a hotel, who did not want either his or the hotel's name used for fear of retaliation. He said he did not see any Tibetans arrested or injured but said some police were hurt.

China's governor in Tibet threatened to punish rioters.

"We will deal harshly with these criminals in accordance with the law," Champa Phuntsok, chairman of the Tibetan government, told reporters in Beijing. "Beating, smashing, looting and burning _ we absolutely condemn this sort of behavior. This plot is doomed to failure."

He blamed the protests on followers of the Dalai Lama, who fled into exile in 1959 after a failed uprising against Chinese rule and is still Tibet's widely revered spiritual leader.

On Friday, the Dalai Lama appealed to China from his home in exile in Dharamsala, India not to use force and to respect Tibetan aspirations.

Pockets of dissent were also springing up outside China.

In Zurich, Switzerland, police said they fired tear gas at pro-Tibet demonstrators who tried to storm the Chinese consulate. Hundreds of people took part in the protest against the Chinese crackdown. Swiss police said they fired the tear gas when several protesters attempted to break into the consulate.

Tibetan groups want the Swiss government to press China on its human rights record.

In Australia, media reported that police used batons and pepper spray to quell a demonstration outside the Chinese consulate in Sydney. The Australian Associated Press reported that dozens of demonstrators were at the scene and five were arrested.

Dozens of protesters in India launched a new march just days after more than 100 Tibetan exiles were arrested by authorities during a similar rally.

And in Katmandu, police broke up a protest by Tibetans and arrested 20.

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Associated Press writers Anita Chang in Beijing, Ashwini Bhatia in Dehra, India, and Binaj Gurubacharya in Katmandu, Nepal, contributed to this story.

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On the Net:

International Campaign for Tibet: http://www.savetibet.org

Chinese official news agency: http://www.xinhuanet.com