The news website for the government in China's western Xinjiang region says that police shot dead 13 assailants who drove one or more vehicles into a police office building and set off explosives in an attack that injured three police officers.

The Tianshan website said in a brief, one-line report that no civilians were hurt in Saturday morning's attack at a county in Kashgar prefecture.

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.