US missile strikes have been criticised by Pakistan's political parties
Missiles said to have been fired by US unmanned aircraft have killed seven people close to Pakistan's border with Afghanistan, Pakistani sources say.
Two missiles reportedly struck a house in Sararogha, in South Waziristan, and the dead are believed to include suspected militants.
The region is a stronghold of Pakistani Taleban leader Baitullah Mehsud.
US drones have targeted the area with missiles before, in attacks criticised by Pakistani politicians.
Local people said Taleban militants had been operating from the house which was attacked.
When asked about the attack, Adm Mike Mullen, chairman of the US Joint Chiefs of Staff, said he would not talk about the specifics of US operations.
But, speaking to Fox News, he added that the military overall was "carrying out guidance from [US] President [Barack] Obama" in the region.
A villager, named by Reuters news agency as Hakeemullah, said that people were searching the rubble for more casualties.
"It was a Taleban sanctuary, which was destroyed in the attack," an unnamed Pakistani security official told AFP news agency.
"Some foreigners were possibly among those killed."
At least four of the dead are believed to have been foreign militants, unnamed Pakistani officials told the Associated Press.
They added that drones were seen in the air ahead of the strike and Taleban fighters afterwards surrounded the damaged house which was allegedly a militant training facility.
Previous US missile attacks have been aimed at militant groups such as al-Qaeda, which have used the region as a base for attacks inside Afghanistan.
More than 20 such attacks have been carried out on targets in north-western Pakistan in recent months.
The US and Pakistan have had serious disagreements over the Afghan border zone, with Washington unhappy at Pakistani efforts to tackle militants and Islamabad condemning the US drone attacks.
Pakistani leaders had expressed hope that the new US administration would halt the controversial air strikes, saying they fuelled public anger and complicated Pakistan's own counter-insurgency efforts.
But the drone attacks have continued since Mr Obama was inaugurated as US president in January.