In this photo released by the U.S. Navy, the guided-missile cruiser USS Philippine Sea launches a Tomahawk cruise missile at Islamic State group positions in Syria as seen from the aircraft carrier USS George H.W. Bush in the Arabian Gulf on Tuesday, Sept. 23, 2014. Syria said Tuesday that Washington informed President Bashar Assad's government of imminent U.S. airstrikes against the Islamic State group, hours before an American-led military coalition pounded the extremists' strongholds across northern and eastern Syria.(AP Photo/Eric Garst, U.S. Navy)