From exile in India, the Dalai Lama appealed to China not to use force to end the largest, most sustained demonstrations in nearly two decades against Beijings 57-year rule in Tibet. Chinas government in Tibet accused the Dalai Lamas supporters of inciting the unrest and imposed a curfew, ordering people to stay indoors.
Eyewitness accounts and photos posted on the Internet portrayed a chaotic scene in Lhasa, the provincial capital, with crowds hurling rocks at security forces, hotels and restaurants. The U.S. Embassy said Americans had reported gunfire.
Reports of deaths varied and could not be independently confirmed.
Chinas official Xinhua News Agency said 10 people - including two hotel employees and two shop owners - were burned to death, but no foreigners were hurt.
In some of the strongest words yet from officials, regional Tibet government head Champa Phunstok warned Saturday that the authorities will respond forcefully.
Shops were set on fire Friday along two main streets surrounding the Jokhang temple, Tibets most sacred shrine and the heart of Lhasas old city, sending out thick clouds of smoke. Young men set fire to a Chinese flag and a huge bonfire burned in a street. Armed police in riot gear backed by armored vehicles blocked intersections, said a Tibetan guide.
The violence, which came on the fifth day of sporadic and largely peaceful protests, poses difficulties for a communist leadership that has looked to the Aug. 8-24 Olympics as a way to recast China as a friendly, modern power. Too rough a crackdown could put that at risk while balking could embolden protesters, costing Beijing authority in often restive Tibet.
On Saturday, Xinhua said Lhasa had reverted to calm at the wee hours and electricity and phone service, which had been cut for parts of Friday, was being restored.
Witnesses said police were patrolling the streets but things appeared peaceful. Shops were closed but government staff were required to work, said a woman who answered the telephone at the Lhasa Hotel.
Over the centuries, Tibet was at times part of Chinas dynastic empires. Communist forces invaded the region in 1950, to reclaim the Himalayan region and seize the commanding heights overlooking rival India. Pressured to cede more power to the communists, the Dalai Lama fled into exile in 1959 after a failed uprising.
The latest unrest began Monday, the anniversary of the 1959 rebellion, when 300 monks from one monastery demanded the release of other monks detained last fall. But political demands soon came to the fore. Other monks and ordinary Tibetans demanded independence and unfurled the Tibetan flag. Arrests ensued, leading to more protests.
The White House urged China to respect Tibetan culture, while the U.S. ambassador to China urged senior Chinese officials to use restraint in dealing with the protesters, according to State Department Spokesman Sean McCormack.
European Union leaders also appealed to China to show calm in Tibet, but released a statement condemning Chinas handling of the protests so far.