Four gunmen on two motor-bikes targeted the checkpoint on Ring Road in Pishtakhara area of Peshawar, capital of restive Khyber-Pakhtunkhwa province, when they were busy checking vehicles, Haroon Khan from the city's police control office told PTI over phone.
"It seems to be a targeted attack and no one took responsibility for it," Khan said.
Taliban militants frequently target the law enforcing agencies as well as civilians in the north-western region of the country where government forces are fighting the rebels.