At least 10 people were killed when demonstrators rampaged through Lhasa, dashing Beijing's plans for a smooth run-up to August's Olympics.
Police broke up a protest by 200 Tibetans in Nepal's capital on Saturday, beating them with bamboo batons and arresting at least 20, as Tibetan exile communities ramped up demonstrations around the world.
Hundreds gathered peacefully for a candlelight vigil in Dharmsala, India, the headquarters of Tibet's government-in-exile. But gatherings in western China, the United States, Australia and India's capital descended into violence when police tried to disperse crowds of distraught exiles.
Streets in Lhasa were mostly empty Saturday as a curfew remained in place. Eyewitnesses described baton-wielding police patrolling streets as fires from Friday's violence smoldered. Reports of deaths and arrests were varied and could not be independently confirmed.
China's official Xinhua News Agency said 10 people - including two hotel employees and two shop owners - were burned to death, but no foreigners were hurt. The report did not give any other details.
Tibet's main exile group claimed Saturday that it had confirmed reports that Chinese authorities killed 30 Tibetan demonstrators and injured many more, and unconfirmed reports of over 100 deaths.
CBS News correspondent Barry Petersen reports that in Beijing today, the National People's Congress re-elected Hu Jintao as China's president ... the vote, not surprisingly, was unanimous.
Hu made his name in 1989 when he was the Communist party boss in Tibet where he moved quickly and harshly to put down similar protests by Tibetan monks.
This time around he is using the same playbook, act quickly, flood the streets with soldiers, and blame it all on Tibetans out to make trouble on the world stage for China.
The unrest comes two weeks before China's highly anticipated Olympic celebrations kick into high gear with the start of the torch relay, which passes through Tibet.
Sun Weide, a spokesman for the Beijing Olympics organizing committee, said the unrest would not have a negative impact on the Games or the torch relay.
Preparations to carry the Olympic torch across Mount Everest and across Tibet "have been proceeding very smoothly and according to schedule," Sun said.
"The hosting of the Beijing Games is the 100-year dream for Chinese people and I think the Chinese people, including our compatriots in Tibet, very much look forward to hosting the Games," Sun said.
The United States and other governments have urged China to show restraint on the protesters. Meanwhile, International Olympic Committee President Jacques Rogge said a boycott of the Summer Games over China's crackdown would only hurt athletes. (See below.)
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.
"We will deal harshly with these criminals in accordance with the law," Champa Phuntsok, chairman of the Tibetan government, told reporters in Beijing where he was attending a legislative meeting. "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.
From Dharamsala, India, the Dalai Lama appealed to China not to use force, saying he was "deeply concerned," and urged Tibetans "not to resort to violence."
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 latest unrest began Monday, the anniversary of the 1959 uprising, when 300 monks from one monastery demanded the release of other monks detained last fall. But political demands soon came to the fore.
The violence erupted on the fifth day, after police tried to stop monks from protesting in central Lhasa, ordinary Tibetans vented pent-up anger on Chinese, hurling stones and torching shops and cars.
"The protesters yesterday went from attacking Chinese police to attacking innocent people very, very quickly," said a blog entry by a group of Westerners staying in a hotel in central Lhasa near the riot. "Many Tibetans were also caught in the crossfire."
On Saturday, Xinhua said Lhasa had "reverted to calm" and electricity and phone service, which had been cut for parts of Friday, was being restored.
A notice issued by Tibet's high court, prosecutors office and police department offered leniency for demonstrators who surrender before Tuesday. Otherwise, they will be "severely punished," according to a notice carried on official Web sites and confirmed by prosecutors.
Some shops in Lhasa were closed. Tourists were told to stay in their hotels and make plans to leave, but government staff were required to work.
"There's no conflict today. The streets look pretty quiet," said a woman who answered the telephone at the Lhasa Hotel.
Tourists reached by phone described soldiers standing in lines sealing off streets where the rioting occurred. Armored vehicles and trucks ferried soldiers.
"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."
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.