Missiles fired from a suspected U.S. drone slammed into a house used by militants in northwesternkilling seven people, a government official and a witness said.
The identities of victims in Thursday's attack in Kurram region were not immediately known.
CBS News could not independently verify the death toll from the strike. A Taliban commander and a hospital security guard both told CBS News that 24 people were killed. Local media in Pakistan reported that as many as 18 people may have been killed, with between five and 10 more critically wounded.
A senior official in the region said the house targeted was believed to be frequented by Islamist militants. He spoke on condition of anonymity because he was not authorized to release the information.
Villager Ismail Khan said spy planes were seen hovering over the area shortly before the attack, adding local militants had retrieved seven bodies from the destroyed house.
The strike came as Pakistan's opposition leader predicted President Asif Aliin office as police turned away another convoy of protesters trying to reach the capital for a major anti-government demonstration.
The United States has launched more than 30 missile strikes on al Qaeda and Taliban targets close to the Afghan border since last year, killing many militants, including some senior ones, but also civilians.
The missiles are believed fired from unmanned drones launched from neighboring, but the United States rarely acknowledges firing them.
Pakistan routinely protests the attacks as violations of its sovereignty, but many people speculate the two countries have an unwritten deal allowing them.