Renewed violence has broken out in a Tibetan area of western China, with reports of several injuries.
Xinhua news agency said rioters attacked government offices in Garze, Sichuan province, on Thursday evening, leaving one official seriously hurt.
Tibetan exile groups say security forces fired on crowds of civilians, killing at least eight people.
The violence comes weeks after unrest swept through Tibetan areas and Beijing responded with a security crackdown.
Protests were peaceful initially, but later turned violent and ethnic Chinese were targeted.
Tibetan exile groups say Chinese security forces killed dozens of protesters. Beijing says about 19 people were killed in rioting.
Foreign media organisations cannot report freely from Tibetan areas, so it is difficult to confirm facts from the area.
“Local officials exercised restraint during the riot and repeatedly told the rioters to abide by the law,” Xinhua quoted an official with the prefectural government as saying.
“Police were forced to fire warning shots and put down the violence,” the official added.
A UK-based activist group said eight people had been killed in the incident – including at least three women and one monk.
Matt Whitticase of the Free Tibet Campaign said Tibetan exiles in India confirmed that monks had marched on government buildings after two of them were arrested for having pictures of their spiritual leader, the Dalai Lama.
More than 350 monks demanded their release and were joined by about 400 lay people, he said.
Security forces opened fire after the demonstration had begun to disperse, he said.
Chinese authorities have repeatedly blamed the Dalai Lama, who lives in exile in India, for stirring up unrest. The Nobel Peace Prize laureate denies the accusations.