The drone fired two missiles into a vehicle as it drove through Darpa Khel village about four kilometres (two miles) west of Miranshah, the main town in the district of North Waziristan, the security officials told AFP.

"The US drone fired two missiles," one of the officials told AFP on condition of anonymity because he was not authorised to talk to the media.

"Four people were killed in the attack, they were all in the vehicle," he added. The identities of the dead were not clear, but the village is a stronghold for militants fighting against US troops in Afghanistan.