South Korea's Amry Special Warfare Command (SWC) soldiers aim their machine guns in a frozen river during a winter exercise in Pyeongchang, South Korea, Thursday, January 8, 2015. About 200 SWC soldiers participated in this routine two-week winter drill. (Photo by Ahn Young-joon/AP Photo)

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)

Vehicles clog a highway during a hazy day in Beijing, China, Wednesday, February 26, 2014. Beijing remained cloaked in hazardous white pollution hiding much of its skyline Wednesday, despite the announced closures or production cuts at 147 of the city's industrial plants. (Photo by Ng Han Guan/AP Photo)

A South Korean woman looks out at the flood water after a torrential rain storm hit the capital city on July 27, 2011 in Seoul, South Korea. South Korea issued a national crisis warning on as torrential rain caused flooding in parts of the country, killing over 35 with at least ten missing. (Photo by Chung Sung-Jun/Getty Images)

Female North Korean traffic police officers gather in front of bronze statues of the late leaders Kim Il Sung and Kim Jong Il to pay their respects in Pyongyang, North Korea on Saturday, February 16, 2013. North Koreans turned out to commemorate what would have been the 71th birthday of Kim Jong Il who died on December 17, 2011. (Photo by David Guttenfelder/AP Photo)

In this Thursday, April 11, 2013 photo, North Korean female soldiers stand watch on the river bank of the North Korean town of Sinuiju, opposite to the Chinese border city of Dandong. (Photo by AP Photo)

U.S. Marine soldiers from 31st Marine Expeditionary Unit, Battalion landing team deployed from Okinawa, Japan, participate in the U.S. and South Korean Marines joint landing operation at Pohang seashore on March 29, 2012 in Pohang, South Korea. Though South Korean has remained technically at war with North Korea since the end of the Korean War in 1953, the tension of Korean Peninsula has again raised as Pyongyang's new leader Kim Jong-Eun administration announced to launch a “Satellite” between April 12 to 16. (Photo by Chung Sung-Jun/Getty Images)

In a photo taken on September 11, 2019, North Korean students pose for photos in Chonji lake, or “Heaven lake”, as they visit the crater of Mount Paektu, near Samjiyon. Mount Paektu has long been considered the spiritual birthplace of the Korean nation and is a place of pilgrimage for tens of thousands of North Koreans every year, who are trained from birth to revere their leaders. (Photo by Ed Jones/AFP Photo)