In this image provided by the U.S. Air Force, a U.S. Air Force B-1B Lancer, assigned to the 37th Expeditionary Bomb Squadron, deployed from Ellsworth Air Force Base, S.D., prepares to take off from Andersen AFB, Guam, on Saturday, Sept. 23, 2017. The Pentagon says B-1B bombers from Guam and F-15 fighter escorts from Okinawa, Japan, have flown a mission in international airspace over the waters east of North Korea. The U.S. says it’s the farthest north of the Demilitarized Zone that divides the Korean Peninsula that any American fighter or bomber has flown this century.(Staff Sgt. Joshua Smoot/U.S. Air force via AP)