The explosion took place in Lakki Marwat district in the North West Frontier Province. Police say nine of the deceased were policemen, and eight were civilians.

Jameel Khan, a senior police official in the district, told CNN a suicide bomber in an explosive-laden vehicle hit a police building.

On Friday, at least 73 people were killed and 206 people wounded in a suicide attack in southwestern Pakistan. The blast in the city of Quetta occurred during an Al Quds day rally, an annual event in the Arab and Muslim world that criticizes Israeli policies toward Palestinians.

In an apparently unrelated incident Friday in northwestern Pakistan, a suicide bomber blew himself up outside an Ahmadi worship place in Mardan, killing himself and a pedestrian, police said.

Waqif Khan, Mardan's police chief, said guards fired on the suicide bomber when he tried to breach the site's security barrier. After he was injured, the attacker detonated his explosives.

Ahmadis, who call themselves Muslims, are considered heretical and have been persecuted in the Muslim world. Recently, there was fighting between Ahmadis and non-Ahmadi Muslims in Indonesia.

Sunnis and Shiites do not consider the Ahmadis part of Islam because they do not regard Mohammed as the last prophet sent by God. As such, they have been targeted by Islamic extremists.

On Wednesday, a trio of suicide attacks during Shiite processions in Lahore killed 31 people and injured at least 340. The Pakistani Taliban claimed responsibility for the attacks.