In a separate incident earlier on Tuesday, suspected tribal fighters blew up two power pylons in the same district.

   

The autonomy-seeking fighters accuse the central government of exploiting their province's resources without sharing the benefits among its people.

   

The fighters frequently target official buildings, military installations, road and rail links, power lines and gas pipelines.

   

Pervez Musharraf, the Pakistani president, has promised to develop the province of sparely populated deserts and mountains bordering Afghanistan and Iran.