A South Korean vehicle transporting South Korean employees working at the Kaesong Industrial Complex (KIC) inside the North Korean border and products made in KIC passes through a gate at the South's CIQ (Customs, Immigration and Quarantine), just south of the demilitarised zone separating the two Koreas, in Paju, north of Seoul, April 8, 2013. Movement around an atomic test site in North Korea indicates the reclusive state may stage another nuclear test, a South Korean minister said on Monday, an act that would further drive up tensions on the Korean peninsula. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: POLITICS BUSINESS INDUSTRIAL) 

A tablet with one of the pictures posted in the official North Korean Flickr account is seen in this photo illustration taken in Singapore April 5, 2013. North Korea's official Flickr and Twitter accounts were targeted by hackers on April 4. Some of the pictures in the Flickr account were replaced by a caricature of North Korea's leader Kim Jong-un as "Pigsy" from the classic Chinese novel "Journey to the West". REUTERS/Pablo Sanchez (SINGAPORE - Tags: POLITICS SCIENCE TECHNOLOGY TPX IMAGES OF THE DAY) 

A South Korean security guard stands on an empty road, which connects with the Kaesong Industrial Complex (KIC) in North Korea, at the South's Customs, Immigration and Quarantine (CIQ), just south of the demilitarised zone separating the two Koreas, in Paju, north of Seoul, April 4, 2013. North Korea barred entry to a joint industrial complex it shares with the South for a second day on Thursday, Seoul's Unification Ministry said, and demanded extended notice of when hundreds of South Korean workers planned to leave. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: MILITARY POLITICS BUSINESS TPX IMAGES OF THE DAY) 

Soldiers of the U.S. Army's 23rd chemical battalion put on their gear as they give a demonstration of their equipment during a ceremony to give notice of 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. The 23rd chemical battalion left South Korea in 2004 but the battalion with about 250 soldiers returned to the South in January 2013 to support South Korean military and the U.S. troops based in the South, according to the infantry division. REUTERS/Lee Jae-Won (SOUTH KOREA - Tags: MILITARY POLITICS TPX IMAGES OF THE DAY) 

South Korean soldiers of an artillery unit take part in an artillery drill with 155mm Towed Howitzers as part of the annual joint military exercise "Foal Eagle" by the U.S. and South Korea, near the demilitarized zone (DMZ) which separates the two Korea, in Goseong, about 330 km (205 miles) northeast of Seoul April 9, 2013. North Korea warned foreigners in South Korea on Tuesday to quit the country because they were at risk in the event of conflict, the latest threat of war from Pyongyang. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: POLITICS MILITARY TPX IMAGES OF THE DAY) 

A South Korean soldier patrols 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 8, 2013. The North, led by 30-year-old Kim Jong-un, has been issuing vitriolic threats of war against the United States and U.S.-backed South Korea since the United Nations imposed sanctions in response to its third nuclear weapon test in February. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: MILITARY POLITICS) 

A North Korean defector living in Seoul conducts a choir during a divine service held to pray for peace and reunification of the divided Korean Peninsula at a church in Seoul April 7, 2013. North Korea, angry about new U.N. sanctions imposed for its third nuclear weapon test in February, has made increasingly strident warnings of an imminent war with South Korea and the United States. REUTERS/Lee Jae-Won (SOUTH KOREA - Tags: MILITARY POLITICS RELIGION) 

South Koreans look north through binoculars near the demilitarized zone (DMZ) separating North Korea from South Korea in Paju, north of Seoul April 7, 2013. China deplored rising tension on the Korean peninsula on Sunday but said its embassy was operating normally in the North Korean capital and it asked authorities there to ensure its diplomats and other citizens were kept safe. North Korea, angry about new U.N. sanctions imposed for its third nuclear weapon test in February, has made increasingly strident warnings of an imminent war with South Korea and the United States. REUTERS/Lee Jae-Won (SOUTH KOREA - Tags: MILITARY POLITICS) 

A U.S. Army Patriot missile air defence artillery battery is seen at U.S. Osan air base in Osan, south of Seoul April 5, 2013. North Korea has placed two of its intermediate range missiles on mobile launchers and hidden them on the east coast of the country in a move that could threaten Japan or U.S. Pacific bases, South Korean media reported on Friday. The North has said nuclear conflict could break out at any time on the Korean peninsula in a month-long war of words that has prompted the United States to move military assets into the region. REUTERS/Lee Jae-Won (SOUTH KOREA - Tags: MILITARY POLITICS) 

Portraits of North Korea's founder Kim Il-sung (L) and his son and late leader Kim Jong-il hang on the wall of a mock North Korean classroom at a South Korean observation post, just south of the demilitarized zone (DMZ) in Paju, north of Seoul April 5, 2013. North Korea has placed two of its intermediate range missiles on mobile launchers and hidden them on the east coast of the country in a move that could threaten Japan or U.S. Pacific bases, South Korean media reported on Friday. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: POLITICS MILITARY PORTRAIT) 

Journalists wait for South Korean employees to return from the Kaesong Industrial Complex (KIC) as a cleaner looks on, at South Korea's CIQ (Customs, Immigration and Quarantine) office, just south of the demilitarised zone separating the two Koreas, in Paju, north of Seoul, April 3, 2013. North Korean authorities were not allowing any South Korean workers into a joint industrial park on Wednesday, South Korea's Unification Ministry and a Reuters witness said, adding to tensions between the two countries. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: MILITARY POLITICS BUSINESS MEDIA) 

South Korean employees working at the Kaesong Industrial Complex (KIC) change their license plates authorized by North Korea, to South Korean ones, upon arrival at the South's Customs, Immigration and Quarantine (CIQ) area, just south of the demilitarised zone separating the two Koreas, in Paju, north of Seoul, April 4, 2013. North Korea barred entry to a joint industrial complex it shares with the South for a second day on Thursday, the South Korean Unification Ministry said, but would allow 222 South Korean workers to leave the zone through the day. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: BUSINESS INDUSTRIAL POLITICS) 

Members of the Association of Companies at Kaesong Industrial Complex (KIC) look to their left during a news conference, which demanded for transit to KIC to be normalised, at the South's Customs, Immigration and Quarantine (CIQ) office, just south of the demilitarised zone separating the two Koreas, in Paju, north of Seoul, April 4, 2013. North Korea barred entry to a joint industrial complex it shares with the South for a second day on Thursday, Seoul's Unification Ministry said, and demanded extended notice of when hundreds of South Korean workers planned to leave. Banner reads, "normalise transit to KIC". REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: MILITARY POLITICS BUSINESS) 

State media film North Korea leader Kim Jong-un (L) waving to soldiers and civilians during a ceremony at a stadium in Pyongyang April 14, 2012, one day before the centenary of the birth of North Korea founder Kim Il-sung on Sunday. REUTERS/Bobby Yip (NORTH KOREA - Tags: POLITICS MILITARY MEDIA) 

South Korean military vehicles travel during a drill as it snows in Hwacheon, about 20 km (12 miles) south of the demilitarized zone separating the two Koreas and about 120 km (75 miles) northeast of Seoul April 9, 2013. North Korea warned foreigners in South Korea on Tuesday to quit the country because they were at risk in the event of conflict, the latest threat of war from Pyongyang. REUTERS/Lee Jae-Won (SOUTH KOREA - Tags: MILITARY POLITICS ENVIRONMENT) 

A North Korean soldier looks out with binoculars at a outpost along the banks of Yalu River near the North Korean town of Sinuiju, opposite the Chinese border city of Dandong, March 29, 2013. China called for an easing of tensions on Friday as North Korea put its missile units on standby to attack U.S. military bases in South Korea and the Pacific after the United States flew two nuclear-capable stealth bombers over the Korean peninsula. REUTERS/Jacky Chen (NORTH KOREA - Tags: MILITARY)