A US drone attack targeting a vehicle travelling in Pakistan's lawless northwestern tribal belt near the Afghan border killed three militants on Sunday, local security officials said.
The unmanned aircraft targeted the vehicle in Hasan Khel village, around 30 kilometres east of Miranshah, the main town in North Waziristan tribal district, and a known hub of militants.
"US drone fired two missiles, the vehicle is still on fire, we have reports that three militants were killed in this attack," a local security official in Miranshah told AFP.
A security official in Peshawar also confirmed the incident and the toll.
Another security official in Miranshah said that identities of those killed in the strike were not immediately known.
A covert US drone campaign in Pakistan has been stepped up over the last few months with strikes in the tribal belt, which Washington considers as the most dangerous place on earth, taking place with increasing frequency.
More than 250 people have been killed in 47 strikes since September 3, heightening tensions with Islamabad over reported US criticism of Pakistan's failure so far to launch a ground offensive in North Waziristan.
The United States does not as a rule confirm drone attacks, but its military and the Central Intelligence Agency operating in Afghanistan are the only forces that deploy the aircraft in the region.
Officials in Washington say drone strikes are highly effective in the war against Al Qaeda and its allies, killing a number of high-value targets, including the Pakistani Taliban's founding father Baitullah Mehsud.
The leadership of the Haqqani network, which is linked to the Taliban and Al Qaeda, is also based in North Waziristan.
It has been accused of plotting some of the deadliest attacks on US troops in Afghanistan, including a suicide bombing that killed seven CIA operatives at a US base in Khost last December.
Pakistan's foreign ministry said recently it would reject any overtures seeking to allow the drone campaign to be expanded outside the tribal areas, amid US press reports that Washington was seeking to expand the areas inside Pakistan where the pilotless aircraft could operate.
The Pakistani Taliban have claimed responsibility for a number of arson and gun attacks on NATO supply convoys destined for Afghanistan, saying they are in revenge for the drone war.
Washington has attempted to soothe anti-Americanism that is rife throughout Pakistan with increased civilian aid to help the country overcome devastating summer floods, balancing that with its huge military donations.