At least three people were killed and several others injured when a bomb went off in Khyber tribal area of northwest Pakistan on Wednesday, local media reported.

According to the report by local Urdu TV channel Dunya, the explosion took place when some unidentified people exploded a roadside planted bomb on a main highway in Bara area of Khyber Agency, a militancy-hit tribal area bordering Afghanistan.

The blast killed three passersby right on the spot while wounding three others, said the report, adding that the injured were shifted a nearby government-run hospital.

Details about the identities of the killed and injured are not known.

Immediately following the blast, the authorities in Bara declared a curfew in the area without giving a definite time for the curfew.

The local government has called for a grand jirga (meeting) on Thursday to discuss the law and order situation in the area. An estimated 120 tribesmen will attend the meeting, said an official with the local government.