A bomb ripped through a bus carrying Pakistani government employees in the northwestern city of Peshawar on Wednesday, killing 15 people, police said.
The explosion took place in an area of the city that houses military institutions and residences.
The bus was taking government employees from several nearby towns to the provincial secretariat in Peshawar, he said.
Nearly 40 people were also wounded in the blast, which was set off by an improvised explosive device that was planted under a seat in the bus, he added.
No one immediately claimed responsibility but suspicion likely is to fall on the Pakistani Taliban and other allied militant groups who have been waging a war on the country for more than a decade.
Local TV footage showed the wreckage of the bus as police and rescue officials rushed the wounded people to hospitals.
Footage from a surveillance camera captured the moment of the explosion, showing the bus moving on a road and then blowing up into a cloud of thick smoke.
Rescuers had to cut through the bus to pull out several of the victims, both dead and wounded, said police official Mubarak Zeb.
Peshawar has been the scene of several major Taliban attacks, including the December 2014 massacre at an army public school in the city that killed 150, mostly children.