The United States killed the leader of Al Qaeda's affiliate in Yemen, the White House confirmed on Thursday. The confirmation came about a week after The New York Times first reported that the United States believed it had killed Qassim al-Rimi, the Qaeda leader, in January after months of tracing him. The C.I.A. carried out the airstrike using an unmanned drone, an intelligence official said. The White House statement had little detail about the operation, but said it was carried out at the direction of President Trump. The statement said Mr. al-Rimi's death will degrade the Yemen affiliate and the global Qaeda movement and "brings us closer to eliminating the threats these groups pose to our national security."