Unidentified gunmen shot dead a police constable escorting a team of polio workers in northwest Pakistan’s restive Khyber Pakhtunkhwa province on Sunday.

The constable was killed by the gunmen riding a motorcycle while he was joining the polio workers in the tribal district of Dhal Behzadi in Kohat district, about 75km south of provincial capital Peshawar.

Members of the vaccination party are said to be safe. No group has taken responsibility for the attack yet.

Police teams rushed to area and started a search operation for the attackers.

Chief minister Mehmud Khan condemned the attack and vowed to arrest the perpetrators.

“Such acts of cowardice cannot deter our resolve to wipe out this crippling disease,” he said.

A five-day vaccination drive is currently underway in Pakistan. The attack took place on the third day.