Police in China's western Xinjiang region shot dead 13 assailants who rammed a truck into a police office building and set off explosives in an attack that wounded three officers, Chinese state media reported.

The local Tianshan website on Saturday said in a one-line report that no civilians were hurt in the attack in Kashgar prefecture in Xinjiang's southwest.

"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.

It was unclear if the attackers used one or more explosive devices.

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

Officials in the region either said they were unclear about the situation or refused to comment, the Associated Press news agency reported.

Authorities have vowed to crackdown in recent weeks and announced a number of arrests and sentences following several high-profile attacks.

In May, 39 people were killed, along with four attackers, and more than 90 wounded when assailants threw explosives and ploughed two off-road vehicles through a crowd at a market in the regional capital Urumqi.

In March, attackers went on a stabbing spree at a railway station in the southwestern city of Kunming that left 29 people dead and 143 wounded.

That incident, one of the first to take place outside Xinjiang blamed on fighters from the region, was dubbed China's "9/11" by state media.

Source: Associated Press