A U.S. drone aircraft killed at least 12 suspected militants on Friday when it fired missiles at a compound in Pakistan near the Afghan border, Pakistani intelligence officials said.
The death toll from the strike in the Dattakhel region in North Waziristan could rise, the officials said.
Many Pakistanis say drone attacks that kill civilians are a violation of Pakistani sovereignty. The attacks are one of several factors straining ties between Pakistan and the United States.
The United States and Pakistan resolved one of their most heated disputes this week when U.S. Secretary of State Hillary Clinton apologized for an air attack that killed 24 Pakistani soldiers last November.
The apology paved the way for Pakistan to permit trucks carrying NATO supplies to cross into Afghanistan for the first time in more than seven months.
The CIA has stepped up drone attacks in North Waziristan in recent weeks in an area seen as a hub for militant groups who attack U.S. forces and their allies in Afghanistan.
Eight people were killed there in a drone strike on Sunday.