Three brothers were killed and another person injured when an improvised explosive device (IED) detonated in the Kali Bakhtiar Khan area of Dukki, police said on Saturday.
According to Superintendent of Police Mansoor Ahmed Buzdar, the explosion struck a vehicle as it was passing through an area described as a pond or ravine.
The victims were identified as Rehmatullah, Durrani and Naimatullah, all biological brothers.
Another man, Atiqullah, was injured in the explosion and taken to a nearby hospital for treatment.
Police described the incident as a terrorist attack and launched a search operation in the surrounding area to identify and arrest those responsible.
No group was immediately reported to have claimed responsibility for the attack.