At least 16 people were killed when a car bomb exploded at a market in northwest Pakistan on Saturday.
Twenty-five others were injured in the blast in Darra Adam Khel, a town 30 minutes from Peshawar.
Officials say the bomber appeared to target members of a pro-government militia set up to fight the Taliban.
Pakistani authorities are encouraging tribal groups to help root out fighters from the militant Islamist movement.
Local media says several people are in a critical condition. Many were transported to hospitals in other towns because of a lack of resources.
Two years ago, more than 70 people were killed in a suicide attack on a mosque in the same town.