BEIJING - Trading fireworks for somber prayer, Tibetans marked Wednesday's arrival of their new year with mourning as Chinese authorities sealed off Tibet and Tibetan regions in western China to foreigners.

An unofficial Tibetan boycott of festivities was in memory of last year's victims of a harsh Chinese crackdown on anti-government protests. The Dalai Lama, Tibet's spiritual leader, said celebrations would be "inappropriate."

At temples in Tibet's capital of Lhasa, rifle-toting Chinese paramilitary guards replaced crowds of pilgrims, and candlelight vigils were held instead of the usual merrymaking, Tibetan groups said.

"The Chinese government is flooding Tibet with troops and attempting to force Tibetans to celebrate the New Year against their will but, in spite of incredible risks to themselves, Tibetans remain defiant," Lhadon Tethong, executive director of Students for a Free Tibet, said in an e-mail.

Adding to the tensions, next month marks the 50th anniversary of a failed 1959 uprising against Chinese rule that led to the Dalai Lama's flight into exile.

China claims that Tibet has always been part of its territory, but many Tibetans say the Himalayan region was virtually independent for centuries and that Beijing's tight control is draining them of their culture and identity.

Several travel agencies in the southwestern city of Chengdu, a popular gateway to Tibet, confirmed Wednesday that Tibetan tourism officials have ordered a ban on foreign travelers in Tibet during February and March because of the Tibetan new year, known as Losar.

"We were given orders that foreign tourists cannot travel to Tibet from Feb. 24 to March 28," said a booking agent who only gave his English name, Joe, for fear of reprisals. "They do this every year for security reasons; it just happens the time length is a bit longer this year."

A woman who answered the phone at the Tibet government tourism bureau said the staff was on holiday.

Tibet is off-limits to international journalists, but foreign tourists are normally allowed as part of group tours. However, security is higher because of unrest a year ago, when deadly riots in Lhasa spread into neighboring provinces as anti-government protests.

The Chinese government says 22 people died in the Lhasa protests, but Tibetan rights advocates say many more were killed, while monks, nuns and villagers were beaten, fined or jailed. State media say 76 people have been sentenced for taking part in the demonstrations, and more than 950 detained.

Travel is also restricted this year in Tibetan areas of Gansu, Sichuan and Qinghai provinces. Armed police were seen last week marching through towns, while security checkpoints had been set up on key roads.

In the days before the new year, monasteries in Tibetan areas were nearly empty and villages were subdued.

But government officials in Tibet reached by telephone Wednesday said they saw no evidence of disruptions.

"All I can see is that everybody is celebrating a normal and festive holiday," said Fu Jun, a spokesman for the regional Communist Party committee in Lhasa.

Cairang, a government official from Xiahe in Gansu province who like many Tibetans uses just one name, said he had not heard of a boycott. A government spokesman in Aba, a Tibetan prefecture in western Sichuan province that remained locked down long after last year's protests, said festivities appeared to be going on as normal.

In Dharmsala, India, home to the Dalai Lama, monks beat ceremonial drums and blew horns during morning prayers to usher in the new year. But more raucous celebrations, with firecrackers and Tibetan beer, were missing.

Fifty volunteers, many of them monks and nuns, started a three-day hunger strike Wednesday to protest Chinese rule in Tibet.

"China's viewpoint is that everyone is happy under China's rule. This decision of Tibetans not to celebrate Losar is a mild form of civil disobedience," said Thupten Samphel, official spokesman of the Tibetan government-in-exile. Lian Xiangmin, a professor at the government-backed China Tibetology Research Center, acknowledged the influence of the Dalai Lama, who is revered by most Tibetans.

"The month of March is sensitive, and the main reason is that the exile government of Tibet and its actions have influence in China," he said.