The United States carried out an airstrike in January that killed a leader of Al Qaeda's affiliate in Yemen after months of tracking him, according to current and former government officials. Qassim al-Rimi, 41, was killed in the January strike but officials had been waiting to confirm the information before making public statement, the New York Times reports. The Yemen branch, Al Qaeda in the Arabian Peninsula, has been keen to attack the U.S. and Europe. Confirmation of al-Rimi's death would mean a significant blow for the group.