The explosion took place at Mithra when a police van was passing by the area while the second explosion took place when police and rescuers were trying to help casualties.
"Around 4.5 kilograms of explosive material was used in the bombs," SSP Abdul Majid Marwat was quoted as saying.
Police cordoned off the area after the attack, however; no arrest has been made yet.
Any group is yet to responsibility of the attacks.However, Pakistani Taliban regularly target military and civilian installations as part of a conflict which has claimed tens of thousands of lives.
In January this year, Bacha Khan University in Charsadda, also in northwest Pakistan was attacked the Tehreek-e-Taliban group (TTP), which left 21including students and teachers dead.