The sources said that the blast occurred in a market in Salarzai Tehseel of Bahaur Agency, killing two and injuring three critically injured.
They said that the bomb was detonated by a remote control device. Heavy contingent of forces rushed to the spot and cordoned off the area.
The dead and injured were shifted to a nearby hospital. No one has claimed responsibility for the blast so far.
Official sources said the man who detonated the bomb was arrested shortly after the incident.