North Koreans work at a factory of South Korean-owned company in the inter-Korean industrial park in Kaesong, North Korea, just a few hundred metres north of the heavily fortified Demilitarised Zone that divides the Korean peninsula in this September 30, 2009 file photo released by Unification Ministry to Reuters on October 28, 2009. REUTERS/Unification Ministry/Handout (NORTH KOREA POLITICS) FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS