evidence: North Korea is taking steps to "completely separate" its territory from the South by cutting off all road and rail links and building fortifications in their place, Kim Jong Un's regime said on Wednesday. [...] North Korea said it would fortify its side of the de facto border with "strong defense structures," without elaborating. A "telephone message" communicating its intentions was sent to U.S. forces "to prevent any misjudgment and accidental conflict over the fortification project," the army said. [...] Seoul said it had yet to detect any construction work by Pyongyang's troops near the Demilitarized Zone, which has been heavily mined by North Korean soldiers in recent months. It said South Korean forces would "overwhelmingly punish" any provocation by the North.