US missiles flattened a fort used as a Taliban training centre in Pakistan's tribal belt on Wednesday, killing 11 militants, the latest in a recent spike of drone attacks, officials said.
A drone fired two missiles into the mud-brick fort in Sanzali village, about 30 kilometres (19 miles) west of Miranshah, the main town in North Waziristan, in the fourth suspected US missile attack in the tribal district in a week.
Just over an hour later, a suspected drone slammed another missile into a group of militants sifting through the wreckage, searching for survivors and picking out the dead bodies, Pakistani security officials said.
"Two foreigners died in the initial attack," a senior security official in the northwestern city of Peshawar told AFP. Their nationalities were not clear. Arab, Uzbek and Afghan militants are present in the area.
"Five militants were killed in the previous attack and six in this attack," the official added, speaking on condition of anonymity.
The area is a stronghold of Hafiz Gul Bahadur, who fought with the Taliban when US-led troops invaded Afghanistan and is reputed to control up to 2,000 fighters whom he sends across the border but who do not attack in Pakistan.
The United States does not confirm drone attacks, but its military is the only force that deploys combat drones in the
"It was a huge, fort-like mud-house. They were using it as a training centre and the training centre belonged to Hafiz Gul Bahadur," a Pakistani intelligence official told AFP, again on condition of anonymity.
Another Pakistani security official put the overall death toll at 13.
Suspected US drones have increasingly targeted North Waziristan, a bastion of Al-Qaeda fighters, the Taliban and the Haqqani network that attacks the 113,000 NATO and US troops fighting in neighbouring Afghanistan.
Washington has put Pakistan at the heart of a new strategy for turning around the eight-year war against the Taliban in Afghanistan, hinging success on dismantling militant sanctuaries along the porous border.
Washington is increasing pressure on Pakistan to tackle militants who use its soil to launch attacks in Afghanistan and American officials have said that the highly secretive drone programme has eliminated some top fighters.
But the attacks on Pakistani territory fuel anti-American sentiment in the nuclear-armed Muslim nation and the government publicly condemns the strikes. Analysts say, however, that the strikes have Islamabad's tacit approval.
At least 74 US drone missile strikes have killed more than 680 people in Pakistan since August 2008.
North Waziristan neighbours South Waziristan, where Pakistan has been focusing its most ambitious military offensive yet against homegrown Taliban militants. It sent about 30,000 troops into the region on October 17.