Security forces in China have shot dead 13 people in the troubled Xinjiang region after they drove into a police building and set off an explosion, state media reported.

"Today thugs crashed a car into the public security building of Kargilik county in Xinjiang's Kashgar prefecture and set off an explosion. Police took decisive action and shot dead 13 thugs," the official Tianshan web portal reported on Saturday, adding that three police were injured.

It was the latest in a series of attacks pointing to growing unrest in the sprawling region, where the native Muslim Uighur people want more autonomy from Beijing.

Last month, a market bombing killed 43 people in Xinjiang's capital, Urumqi.

In March, a knife assault at a railway station in the southern city of Kunming left 29 dead and 143 wounded.

Chinese authorities have blamed the attacks on "extremists" bent on overthrowing Beijing's rule.

Andrew Leung, a China analyst from Hong Kong, told Al Jazeera that the situation in Xinjiang is turning "from bad to worse."

"The local residents feel marginalised because there is a huge influx of Han [Chinese]," he said.

Exiled Uighur groups and human rights activists also said China's own repressive policies in Xinjiang have provoked the unrest.

Authorities in Xinjiang have arrested dozens of suspects in recent weeks for spreading "extremist" propaganda, possessing banned weapons and other crimes.

Last Monday, China executed 13 people accused of terror attacks in Xinjiang.