No group immediately claimed responsibility, but the Pakistani Taliban have staged similar attacks in the tribal region of Darra Adam Khel to punish elders for backing security forces in offensives against militants.

The explosives-laden car was parked near the office of one of the so-called peace committees that have been formed by local elders trying to rid the area of militants, regional government administrator Fakhruddin Khan said.

It was unclear how many people were in the office at the time, but Khan said those killed included tribal elders and passers-by.

He said 40 people also were wounded and the attack destroyed 35 shops and eight vehicles. The dead and wounded, including some in critical condition, had been transported to hospitals in the northwestern city of Peshawar.

The region, which is in the Khyber Pakhtunkhwa province, is famous for its weapons market selling guns made by local craftsmen....