A missile that struck a house in a Pakistani region killed 13 suspected militants, intelligence officials said.
The attack took place near Kaloosha village in the South Waziristan tribal region on the Afghan border.
A security official said he believed the missile was fired by US forces who are operating in neighbouring Afghanistan, and that the house belonged to a Pashtun tribesman, Sher Mohammad Malikkheil, who is believed to have links with militants.
He said the house, about 25km (16 miles) inside Pakistan's border and opposite an US base in Afghanistan, was rented out a couple of months ago.
US forces have fired missiles at militants on the Pakistani side of the border several times in recent years, most recently on January 28 when one of Osama bin Laden's top lieutenants, Abu Laith al-Libi, was killed in a strike in North Waziristan.
That missile was believed to have been fired by a US pilotless drone.