Thirteen people, including two children, were killed and four others injured when the Pakistani Taliban targetted a bu s carrying Shia Muslims with a roadside bomb in the country's restive tribal belt on Wednesday.
The incident occurred in Sepoy village of Orakzai Agency, said officials of the political administration of the semi-autonomous tribal region.
The bomb was triggered by remote control while the bus was passing through the area.
A spokesman for a Pakistani Taliban faction based in Darra Adam Khel told the media that the bus was targetted because it was carrying members of the minority Shia community.
The bombing was the latest in a series of attacks on Shias across the country by the Taliban and other banned terrorist groups.
Seven persons were killed instantly and six more succumbed to their injuries in a nearby hospital. Two women, a three-year-old girl and an 11-year-old boy were among the dead. Officials described the condition of the four injured persons as critical.
Security forces and a local 'lashkar' or anti-Taliban militia launched a search operation after the blast.