Violence erupted in the Tibetan capital of Lhasa today in what is believed to be the largest demonstration against Communist Party rule in 20 years.
Armed police used water cannons and tear gas on demonstrators, while cars and shops were set alight in protest against the regime's occupation of Tibet.
The protests, in their fifth day and led by monks supporting the area's exiled spiritual leader, the Dalai Lama, threaten to cast a pall over the Chinese regime's image of a unified nation ahead of the 2008 Olympics.
The U.S. Embassy in Beijing said that it had "received firsthand reports from American citizens in the city who report gunfire and other indications of violence".
The last mass protest against the regime took place in Tiananmen Square, Beijing, in 1989 when tanks rolled over students who had gathered to call for democracy.
Tibetans are hoping to use the Olympics to draw attention to their plight. The region has been under occupation for 50 years and thousands of monks and nuns have been tortured to death in labour camps.
In recent years, Beijing has used more soft power in the form of investing in the region, vilifying the Dalai Lama, and infiltrating the clergy with Communist Party supporters.
The Dalai Lama, the spiritual leader of Tibet's Buddhists, urged the regime not to use violence to quell the protests, which he called "a manifestation of the deep-rooted resentment of the Tibetan people under the present governance".
He said in a statement: "I therefore appeal to the Chinese leadership to stop using force and address the long-simmering resentment of the Tibetan people through dialogue with the Tibetan people".
Tensions in the Tibetan capital have increased over the past five days. The three biggest monasteries were sealed off by thousands of soldiers and armed police in a crackdown against the protests.
Reports from the capital suggest that Tibetan protestors have set fire to cars and shops.
One Tibetan woman, who has family in the city but who wished to remain anonymous for fear of reprisals, told Associated Press that protestors were setting fires.
"The monks are still protesting. Police and army cars were burned. There are people crying," she said. "Hundreds of people, including monks and civilians are in the protest."
Monks at the major Sera Monastery were said to have launched a hunger strike Thursday to demand that armed police withdraw from the monastery grounds and detained monks be released.
Also believed to be guarded is the Drepung Monastery and Ganden.
According to the International Campaign for Tibet, monks from the Ganden monastery mounted protests Thursday, becoming the last of the three historically important monasteries known as the "Three Pillars of Tibet" to join in the demonstrations.
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