Pakistani intelligence officials say a U.S. drone strike has killed at least 20 militants in the North Waziristan tribal region along the Afghan border.

The officials said the unmanned aircraft fired two missiles into a house Wednesday near the town of Miranshah, and that the militants include members of the Haqqani network. The militant group is affiliated with the Taliban and al-Qaida.

U.S. officials do not publicly acknowledge the use of such strikes inside Pakistan but privately have confirmed their existence to various news outlets. Pakistan has condemned the attacks as a violation of its sovereignty, but the drone strikes are believed to be carried out with the help of Pakistani intelligence.