A doctor and a policeman were injured when unknown assailants opened fire on a vehicle deployed for anti-polio campaign in the Bajaur district of Khyber Pakhtunkhwa on Friday. According to police and rescue officials, the incident took place when the vehicle was returning from District Headquarters Hospital Khar in Turkho area of ??Mamond tehsil, a private news channel reported. The injured were shifted to the District Headquarters Hospital for immediate medical assistance.