In late September, B-1 bombers flew the first mission this century north of the demilitarized zone (DMZ) that divides North and South Korea
. Accompanied by U.S. Air Force F-15 fighters, the bombers flew the mission more than 200 miles east of the Korean Peninsula. At the time, the Pentagon 's chief spokesman said the mission was in response to North Korea
's recent ICBM and nuclear tests.