共同警備区域
On August 18, 1976, US Army Captain Arthur Bonifas and Lieutenant Mark Barrett were killed by the North Korean Army with axes at Panmunjom when the Americans, over objections of North Koreans, continued trimming a tree that blocked the view of the U.S.-South Korean military unit patrolling the Joint Security Area—an intensely guarded and combative area in the middle of the DMZ separating North and South Korea. President Ford responded with a show of force, authorizing DEFCON 3, a high state of military readiness. The North Korean government backed down and allowed the tree-cutting to go ahead in what the U.S. military termed "Operation Paul Bunyan." North Korea's leader said the incidents in the Joint Security Area were "regretful" but stopped short of meeting U.S. demands for a formal apology.