A suicide bomber killed at least 15 people, most of them police, outside a polio eradication centre in the Pakistani city of Quetta on Wednesday, the latest militant attack on the anti-polio campaign in the country.
Two militant groups the Pakistani Taliban and Jundullah, which has links with the Taliban and has pledged allegiance to Islamic State - separately claimed responsibility for the attack.
"It was a suicide blast, we have gathered evidence from the scene," Ahsan Mehboob, the provincial police chief told Reuters.
Ahmed Marwat, who identified himself as a commander and spokesman for Jundullah, said his group was responsible.
"We claim the bomb blast on the polio office.
In the coming days, we will make more attacks on polio vaccination offices and polio workers," he said by telephone.