A South Korean soldier runs past a barricade at a checkpoint on the Grand Unification Bridge, which leads to the demilitarized zone separating North Korea from South Korea, in Paju, north of Seoul, April 17, 2013. North Korea issued new threats against South Korea on Tuesday, vowing "sledge-hammer blows" of retaliation if South Korea did not apologize for anti-North Korean protests the previous day when the North was celebrating the birth of its founding leader. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: POLITICS MILITARY)