A bomb explosion targeted policemen going to provide security for polio vaccination workers in Pakistan's restive Khyber Pakhtunkhwa province on Monday, killing six of them and injuring 22 others.
The incident occurred in the Mamund tehsil of Bajaur district in the province bordering Afghanistan.
The police personnel had just boarded a van to join security duty with polio vaccination teams when the explosion occurred.
The injured have been shifted to a nearby hospital, where an emergency was declared.
Six policemen were killed and 22 others injured in the explosion.
The police spokesperson said all the casualties were of police personnel.
Caretaker Chief Minister KPK Arshad Hussain condemned the attack and said the war against terrorism would go on till the elimination of the last terrorist.
Polio teams are often targeted by militants in Pakistan due to opposition to the vaccine.
There was no immediate claim of responsibility for the attack but Islamist militants, including the Pakistan Taliban, have killed scores of polio vaccination workers and policemen guarding them in the past.
