At least seven people were injured when a remote-controlled bomb hit a police checkpost in Peshawar on Sunday morning, said police.

Three of the injured people were in critical condition, said hospital sources.

Superintendent Police Rural in Peshawar Shafiq Ullah told media that the blast took place at about 10:15 a.m. local time near a checkpost outside a cattle market at the Ring Road of the city.

The bomb was hidden inside a pressure cooker which was planted near the checkpost, said the police officer, adding that an estimated five kilograms of explosives were used in the bomb.

The blast destroyed four vehicles nearby apart from wounding seven people and killing several animals, he said.

A media report said that seven to eight police were posted in the checkpost when the blast went off and the injured people also included several policemen.

Police believed that the recent repeated attacks on police in Peshawar could be retaliation by militants for a search operation being launched in the Bara area of Khyber Agency, a tribal area which borders on Peshawar.

On Saturday, a remote-controlled bomb hit a police convoy in Peshawar, killing two people and injuring 16 others. Over the last five days, blasts were reported in the city almost on a daily basis.