Chinese President Xi Jinping (right) and South Korean President Park Geun-hye greet children waving the two countries' national flags at the presidential Blue House in Seoul on Thursday. Xi has yet to visit North Korea. Kim Hong-ji/Reuters/Landov hide caption

itoggle caption Kim Hong-ji/Reuters/Landov

A propaganda painting is seen outside the People's Palace of Culture in Pyongyang, North Korea, in 2011. North Korean state media reported Friday that the nation has detained a U.S. tourist. Feng Li/Getty Images hide caption

itoggle caption Feng Li/Getty Images

North Korea apparently doesn't like either of them: President Obama and South Korean President Park Geun-hye at a news conference in Seoul, South Korea, on Friday. Carolyn Kaster/AP hide caption

itoggle caption Carolyn Kaster/AP

This image was taken Jan. 30 by astronauts aboard the International Space Station. North Korea is the large dark patch in the middle. The only significant light is from its capital, Pyongyang. The next photo adds reference points. NASA.gov hide caption

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South Korean Park Yang-gon (left) and his North Korean brother Park Yang Soo get emotional as they meet Thursday during the Separated Family Reunion Meeting at Diamond Mountain resort in North Korea. Park Hae-soo/AP hide caption

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A North Korean KN-08 intercontinental ballistic missile rolls past in a military parade in Pyongyang in July to mark the 60th anniversary of the Korean War armistice. A team of U.S. researchers recently found the buildings where the North Korean military is believed to be assembling the launchers. David Guttenfelder/AP hide caption

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In this handout image provided by the South Korean Unification Ministry, Kim Kyou-Hyun (right) the head of South Korea's high-level delegation, shakes hands with his North Korean counterpart Won Tong-Yon before their meeting Wednesday in Panmunjom, South Korea. /Getty Images hide caption

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Wang Yu-chi, head of Taiwan's Mainland Affairs Council, left, shakes hands with Zhang Zhijun, director of China's Taiwan Affairs Office, before their meeting in Nanjing, China, on Tuesday. Alexander F. Yuan/AP hide caption

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