A perpetrator drove a car packed with explosives into the facility, several media outlets report.
At least 16 people were killed and many more injured, the Pakistani newspaper Dawn reports. Several of the dead were reportedly police officers.
The mosque is located next to a police building, and the blast was described as powerful enough to damage many houses in the area. The mosque is in the city of Kohat, in a province that borders Afghanistan to the west.
Authorities did not initially name anyone responsible for the attack. The region has seen many violent attacks in recent years that have been attributed to the Pakistani Taliban movement, the TTP, which has strained relations between Pakistan and the Taliban regime in Afghanistan.
