Peshawar: Four policemen, who were escorting a polio vaccination team, were on Friday killed and two injured when unknown assailants opened fire at them in Pakistan's restive Khyber Pakhtunkhwa province, police said.
The incident occurred in the Gul Iman area of Tank district when unknown gunmen ambushed the police mobile van during a door-to-door oral polio vaccination drive.
Two cops, who were injured in the firing, have been rushed to a nearby hospital.
The police have launched a search operation in the area.
The firing between the police and the attackers continued for quite a long time, locals said.