In this Sept. 23, 2014, photo, released by the U.S. Air Force, a pair of U.S. F-15E Strike Eagle flies over northern Iraq, after conducting airstrikes in Syria. U.S.-led coalition warplanes bombed oil installations and other facilities in territory controlled by Islamic State militants in eastern Syria on Friday, Sept. 26, 2014, taking aim for a second consecutive day at a key source of financing that has swelled the extremist group’s coffers, activists said. (AP Photo/U.S. Air Force, Matthew Bruch)
