A US drone fired two missiles into a compound used by Islamist fighters in Pakistan's tribal belt on Tuesday, killing at least six militants, security officials said.
The missiles targeted the compound in Karikot village, about 10 kilometres southwest of Wana, the main town in South Waziristan district, a senior security official told AFP on condition of anonymity.
"Six militants have died in the attack and at least two were wounded," he said. The compound belonging to a militant commander, Maulana Halimullah, had been destroyed.
"The dead included some foreign militants," he said, using official Pakistani jargon for Al-Qaeda militants.
Officials in Wana also confirmed the attack and the toll.
South Waziristan, considered a stronghold of militants, was the scene of a major Pakistani offensive last year.
The district borders North Waziristan, where a similar drone strike on Sunday also killed six militants.
Washington has branded the rugged tribal area on the Afghan border a global headquarters of Al-Qaeda and the most dangerous place on earth.
Around 950 people have been killed in more than 100 drone strikes in Pakistan since August 2008, including a number of senior militants. However the attacks fuel anti-American sentiment in the conservative Muslim country.
The US military does not, as a rule, confirm drone attacks, but its armed forces and the Central Intelligence Agency operating in Afghanistan are the only forces that deploy pilotless drones in the region.
Militants based in the rugged tribal terrain attack US-led forces across the border in Afghanistan, where the Afghan Taliban are waging a nearly nine-year insurgency to evict the estimated 140,000 foreign troops.
On June 1, Al-Qaeda said its number three leader and Osama bin Laden's one-time treasurer Mustafa Abu al-Yazid had been killed in what security officials said was an apparent drone strike in North Waziristan.