A South Korean businessman changes his South Korean license plate to one authorized by North Korea before leaving the South's CIQ (Customs, Immigration and Quarantine) office to go to the inter-Korean Kaesong Industrial Complex in North Korea, just south of the demilitarised zone separating the two Koreas, in Paju, north of Seoul, April 1, 2013. North Korea said on Saturday it was entering a "state of war" with South Korea, but Seoul and the United States played down the statement as tough talk. Pyongyang also threatened to close a border industrial zone, the last remaining example of inter-Korean cooperation which gives the North access to $2 billion in trade a year. REUTERS/Lee Jae-Won (SOUTH KOREA - Tags: TRANSPORT POLITICS BUSINESS)