The early morning attack took place 10 kilometers east of Miranshah, the main town of North Waziristan, according to the officials, who asked not to be identified because they were not authorized to speak to the news media on the matter.

North Waziristan is one of seven districts in Pakistan’s tribal region along the Afghan border and widely believed to be a haven for the Haqqani network and other militant groups that are fueling the insurgency in Afghanistan.

The attack Wednesday morning was the fourth suspected U.S. drone strike on Pakistani soil this year, all of them targeting locations in North Waziristan.

There has been a sharp drop in the number of drone attacks in Pakistan since a NATO airstrike in November killed 24 Pakistani soldiers, driving U.S.- Pakistan relations to a low point.

The Pakistani government shut down the two NATO supply routes in the country after the attack and has since been reviewing its partnership with the United States.