At least three people were killed after a bomb went off in Khyber Pakhtunkhwa's Upper Dir district on Sunday.

The blast, which occurred in the Gumadand area of the Sheringal tehsil, left at least a dozen people injured, said police.

Upper Dir District Police Officer (DPO) Naseeb Jan confirmed the incident saying that three people had been killed while 19 others were injured, including two policemen.

According to the DPO, an improvised explosive device (IED) had been planted on the roadside which was detonated as a double-cabin vehicle was passing by.

"The victims have an old enmity with another family who fled the area and reportedly joined Taliban," the officer told DawnNewsTV, adding that the two families target each other whenever they get a chance.

All the injured were shifted to a hospital, where five were said to be in critical condition. Police have started a search operation but no arrests have been made so far.