North Korean military participate in the celebration of the 70th anniversary of the founding of the ruling Workers' Party of Korea, in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang on early October 11, 2015. (Photo by Reuters/KCNA)

In this Friday, August. 17, 2018, photo, a North Korean waitress prepares to serve dinner to Chinese tourists at the Pegaebong hotel in Samjiyong in North Korea. Chinese businesspeople and tourists are once again flowing over the borders – several large tourist groups were in Samjiyon last week – and South Korean officials are seriously considering ways to help the North improve its roads and railways. (Photo by Ng Han Guan/AP Photo)

A member of North Korean military holds flowers to be laid at the bronze statues of the late leaders Kim Il Sung and Kim Jong Il at Mansu Hill Grand Monument in Pyongyang, North Korea, Monday, December 17, 2018. North Koreans are marking the seventh anniversary of the death of leader Kim Jong Il with visits to the statues and vows of loyalty to his son, Kim Jong Un. (Photo by Dita Alangkara/AP Photo)

North Koreans perform during a mass game of “The Land of the People” at the May Day Stadium in Pyongyang, North Korea, Tuesday, June 25, 2019. (Photo by Jon Chol Jin/AP Photo)

A man reacts after catching a trout with his hands during an event promoting the Ice Festival on a frozen river in Hwacheon, about 20 km (12 miles) south of the demilitarized zone separating the two Koreas, January 10, 2015. The annual ice festival, which is one of the most famous and biggest festivals in South Korea, expects to see more than 1,000,000 people attend. The festival lasts for three weeks from January 10 this year. (Photo by Kim Hong-Ji/Reuters)

Amphibious assault vehicles of the South Korean Marine Corps throw smoke bombs as they move to land on shore during a U.S.-South Korea joint landing operation drill in Pohang March 31, 2014. The drill is part of the two countries' annual military training called Foal Eagle, which began on February 24 and runs until April 18. (Photo by Kim Hong-Ji/Reuters)

North Korean commuters are seen through a door window waiting to board a train in a subway train station in Pyongyang, North Korea, 14 April 2017. North Koreans are preparing to celebrate the “Day of the Sun” festival, commemorating the 105th birthday anniversary of former supreme leader Kim Il-sung on 15 April, as tension over nuclear issues rise in the region. (Photo by How Hwee Young/EPA)

A woman directs traffic in the pouring rain in Pyongyang, North Korea on May 3, 2016. The city is preparing for the Workers' Party Congress starting on May 6th. It will be the first time since 1980 that the ruling party has convened. (Photo by Linda Davidson/The Washington Post)