Islamabad, Sep 7 (IANS) A powerful explosion in the family quarters of the police lines in a northwestern Pakistani city killed at least four people and injured over 20, an official said.

The injured in the blast in Kohat city included women and children. The toll was likely to increase and officials had cordoned off the area to start rescue operations.

Eyewitnesses said a vehicle hit a wall of the police quarters and blew up.

Kohat Commissioner Khalid Umarzai confirmed the blast but refused to give any details.

A suicide blast targeting a police station in Lakki Marwat Monday killed 19 people including nine policemen and nine school-going children.