A bomb planted in a car exploded on Saturday killing three passengers and wounding two pedestrians in a Pakistani tribal area on the border with Afghanistan, officials said.
The bomb, which was on a timer, exploded in a moving car at Barqambarkhel village in the lawless Khyber tribal district, they said.
"Three people were killed and two pedestrians were wounded when a time bomb planted in a car exploded," Khyber's top administrative official Shafirullah Khan told AFP.
The wounded were in stable condition, he added.
Local intelligence officials confirmed the incident and the death toll.
Khyber is home to Taliban insurgents and militants from the extremist group Lashkar-e-Islam, led by local warlord Mangal Bagh.
Washington has branded the tribal belt a global headquarters of Al-Qaeda and wants Pakistan to do more to fight insurgents streaming across its border into Afghanistan.