1South Korean soldiers take part in military training near the demilitarized zone separating the two Koreas in Paju, north of Seoul, April 4, 2013.
2U.S. soldiers wear gas masks while attending a demonstration of their equipment during a ceremony to recognize the battalion's official return to the 2nd Infantry Division based in South Korea at Camp Stanley in Uijeongbu, north of Seoul, April 4, 2013.
3South Korean vehicles turn back after being refused entry to Kaesong, North Korea, April 3, 2013.
4Anti-war protesters raise signs during a rally denouncing the joint military drills between the South Korea and the United States near the U.S. Embassy in Seoul, South Korea, April 3, 2013.