The blast took place in the Peshawar Chowk area near the Police Lines.
Inspector General of Khyber Pakhtunkhwa police, Nasir Khan Durrani said the blast took place near a passenger vehicle. He said the blast appeared to have been carried out using a planted explosive device.
Durrani said that according to initial reports, five kilograms of explosives were used in the blast which were planted in a wooden crate placed on the roadside.
The explosives were detonated as a passenger vehicle reached Peshawar Chowk.