At least 27 people have been killed after gangs armed with knives attacked a police station and a local government building in a remote region of western China today, according to state media.
The Xinhua agency said mobs in the Xinjiang region - home to a large Muslim Uighur minority - set upon buildings in the township of Lukqun at around 6am local time, stabbing people and setting fire to police cars.
Nine police officers and security guards and eight civilians were killed before police opened fire on the attackers, leaving 10 dead, regional Communist Party officials told the agency.
The reported unrest in the region was the deadliest since July 2009, when nearly 200 people were killed in riots pitting Uighurs against ethnic Chinese in the region's capital Urumqi.
The reasons for today's attacks were not immediately clear.
Many Uighurs, who speak a Turkic language, chafe at what they call Chinese government restrictions on their culture, language and religion.
China says it grants Uighurs wide-ranging freedoms and accuses extremists of separatism.
Xinjiang is ruled by China's Han ethnic majority.
It has been the scene of numerous violent incidents in recent years.
The report said three rioters were seized, and that police pursued fleeing suspects, though it did not say how many.
A further three people were injured in the unrest today, Xinhua said.
The state media report has not been independently confirmed.
Information is tightly controlled in the region, which the Chinese government regards as highly sensitive and where it has imposed a heavy security presence to quell unrest. However, forces are spread thin across the vast territory and the response from authorities is often slow.
An official reached by phone at the press office of the Xinjiang Public Security Bureau, the region's police, told the Associated Press she had only seen news of the violence on the Internet and had no information.
Other officials at the county's propaganda department and police said they also had no details. Calls to the region's government spokeswoman, Hou Hanmin, rang unanswered.
An overseas Uighur activist said the conflict was triggered by the Chinese government's 'sustained repression and provocation' of the Uighur community.
Dilxat Raxit, spokesman for the Germany-based World Uyghur Congress, urged the international community to pressure China to 'stop imposing policies in Xinjiang that cause turmoil'.
China often accuses overseas Uighur activists of orchestrating violent incidents and obscure militant groups sometimes take responsibility, with little or no evidence to prove claims on either side.