
One eyewitness told the BBC how large groups of people were setting fire to cars and shops and destroying anything of Chinese influence.
Tibet's spiritual leader, the Dalai Lama, released a statement expressing deep concern, saying the protests were a "manifestation of the deep-rooted resentment of the Tibetan people".
The Dalai Lama, who heads Tibet's government-in-exile in India, called on the Chinese leadership to stop using force and begin dialogue with the Tibetan people.
He said about 300 monks had tried to leave the Sera monastery to protest but security forces brandishing clubs stopped them and at least one monk was beaten to the ground.
many Tibetans remain loyal to the Dalai Lama, who fled in 1959 and currently lives in exile in India.