WASHINGTON—The U.S. launched a recent drone strike against the leader of al Qaeda’s Yemen branch, although it wasn’t clear on Friday whether he was killed as a result, people familiar with the matter said.

The strike in Yemen was aimed at Qasim al-Raymi, the emir, or leader, of al Qaeda in the Arabian Peninsula, long seen as one of the terrorist group’s most potentregional affiliates.

AQAP’s leaders have inspired or directed multiple operations to attack the U.S. directly, including the attempt to blow up a U.S.-bound airliner on Christmas Day 2009.

The strike aimed at Mr. Raymi, who had been mentioned as a possible future leader of al Qaeda globally, was the latest in a string of high-profile military operations against senior U.S. adversaries.

In October, Islamic State’s ideological leader, Abu Bakr al-Baghdadi, was killed in a raid by U.S. special operations force in northwestern Syria. Baghdadi’s spokesman and potential successor was killed in a U.S. airstrike shortly afterward.