Mobs armed with knives have attacked a police station and a local government building in Xinjiang, leaving 27 people dead in the worst violence the restive region has seen.

The unrest erupted early Wednesday in the remote township of Lukqun, about 200 km southeast of Urumqi, the regional capital, when rioters started stabbing people and setting police cars on fire, the official Xinhua news agency reported.

“Seventeen people have been killed – including nine policemen and eight civilians,” Xinhua quoted local authorities. Police allegedly opened fire in the ensuing violence, shooting dead 10 rioters.

The reasons for the attacks were not immediately clear, reports Reuters.

Many Uighurs, an ethnic Muslim group in Xinjiang, has long accused Beijing of oppression with government-encouraged migration of Han Chinese.

The latest unrest was the deadliest since July 2009, when nearly 200 people were killed in riots between Uighurs and Han residents in Urumqi.