Two American missile attacks killed 15 people in north-west Pakistan in an expansion of the CIA-led covert war inside the country.
The strikes took place in two villages in the Tirah Valley in the Khyber region, Pakistani intelligence officers said. The same valley, which is known to be home to militants, was hit late on Thursday night in another US attack.
Most of the more than 100 missile attacks this year inside Pakistan have taken place in North Waziristan, a tribal area effectively under the control of Taliban and al Qaida groups.
The missiles, fired from unmanned drones, hit houses in the villages of Speen Drang and Shandana, the officials said.
The missile attacks have been credited with killing many top militants, but have stirred nationalist anger in Pakistan.
The frequency of the attacks has more than doubled this year compared to last, suggesting the Obama administration see the tactic as a key to reducing the strength of militants planning attacks in Afghanistan and the West.