At least seven people including five school students were killed and 23 injured in a blast in southwestern Pakistan on Friday, a police official said.
"The target was a police van which was going to pickup a polio (vaccination) team," Senior Superintendent of Police Rehmatullah told Reuters. One police officer was also among the dead, while 23 other people and officers were injured.
The explosion came from an improvised device attached to a motorcycle parked near a school for girls in the town of Mastung, he said.
No group has claimed responsibility for the attack.