At least six militants were killed on Monday in an airstrike from a pilotless US aircraft in Pakistan's tribal region near the Afghan border, intelligence officials said.
The drone strike hit a vehicle in the Mir Ali area of North Waziristan, a known stronghold of Taliban and Al-Qaeda militants.
"A drone fired three missiles on a non-custom paid vehicle. Six militants were killed in the attack," an intelligence official who spoke on condition of anonymity said.
A second intelligence official said "some foreigners were also among the killed," using the term locally applied to Al-Qaeda-linked militants of Arab and Central Asian origin.
The official said it was not clear immediately if any high-value targets were among the victims.
The US Central Intelligence Agency has intensified its covert drone war against Taliban and Al-Qaeda operatives who launch cross-border attacks on NATO forces in Afghanistan.
US officials say the drones are a vital tool in their battle against the growing insurgency in mountainous border areas.
More than 850 people have died in nearly 100 drone strikes since August 2008. Several of the victims have been civilians.