Four prisoners broke a prison in this capital of north China's Inner Mongolia Autonomous Region on Saturday after killing a prison policeman, local police said Sunday.

The public security authorities of the region and Hohhot city have dispatched police forces to hunt for the four runaways. Prison management has issued circular through a local television station to solicit tips for their whereabouts.

The four prisoners from the No. 2 Prison in Hohhot are aged between 28 and 21. They ran away at around 1 p.m. Saturday.