The blast occurred in a truck at roadside in Chahrmang area of Nawagai, officials said.
The injured were taken to Agency Headquarter Hospital. Seven of the injured are said to be in critical condition.
The casualties are all said to be locals of the area. Bodies of the deceased were sent to their native towns.
Arrangements were also being made to shift the critically injured to hospitals in Peshawar via helicopter.
Security forces cordoned off the site of the incident and started a search operation in the area.