A U.S. official described the shooting deaths of three U.S. military trainers in Jordan as a "very tragic incident."

The Americans were killed Friday while driving into an air base in southern Jordan. A Jordanian was wounded.

Brett McGurk, White House envoy to the U.S.-led coalition against Islamic State extremists, said Jordan's King Abdullah II expressed condolences in a meeting Sunday. McGurk says an investigation is continuing.

McGurk praised Jordan's role in the fight against IS, which holds territory in neighboring Syria and Iraq.

He says that "nothing will come between Jordan and the United States."

U.S. officials identified the three as 27-year-old Staff Sgt. Matthew C. Lewellen, of Lawrence, Kansas; 30-year-old Staff Sgt. Kevin J. McEnroe of Tucson, Arizona; and 27-year-old Staff Sgt. James F. Moriarty of Kerrville, Texas.