The bomb was planted at a shop in the weekly market at Meherban Kalay village in Khyber Agency on Friday, Jul 16.
Rescue activities had been started and the injured were taken to near by hospitals by the local residents.
The nature of the blast is yet to be found out.
The blast occurred in a place, which is under the influence of the banned Lashkar-e-Islam led by Mangal Bagh Afridi.
Yousuf Raza Gilani, Prime Minister regretted the blast and ordered for a thorough probe.