A US drone struck a vehicle in a terrorist stronghold in Northwest Pakistan's North Waziristan tribal region near Afghan border on Sunday, killing at least four militants.
The spy plane fired two missiles at the vehicle in Doga Madakhel area of the restive Datta Khel sub-division, a region that has witnessed several drone attacks in the past two years, official sources said.
They said four militants were killed in the attack.
CIA-operated drones have carried out more than 100 attacks in North Waziristan tribal agency alone in 2010.
The US has stepped up pressure on Pakistan to move troops into the volatile region to flush out Taliban and al Qaeda elements who target foreign forces across the border in Afghanistan.