The soldier shot and injured by the North Korean side while defecting from a military post in front of Panmungak, the main building managed by North Korea in the Joint Security Area, the JCS said in a statement.
"He is undergoing a second round of operations and we can't reach the operating room as they are working on him", a spokeswoman at Ajou University Hospital told Reuters by telephone, seeking anonymity because of security concerns.
"His organs are extremely damaged. we do not know how long he can hold up", Lee said, describing the soldier's condition as "very serious".
The South Korean ministry official said the soldier's condition and military rank remained to be verified.More news: Southeast Asia summit draft statement skips over Rohingya crisis
The move is considered highly unusual as even defectors from the North rarely cross directly over the border - usually crossing into China first before heading to Seoul - and South Korea's National Intelligence, army and police have launched a joint investigation.
American presidents often visit Panmunjom and other DMZ areas during their trips to South Korea to reaffirm their security commitment to the South. President Donald Trump planned to visit the DMZ to underscore his stance against North Korea's nuclear program when he came to South Korea last week as part of an Asian tour, but his plans were thwarted by heavy fog that prevented his helicopter from landing at the border area.
The Joint Chiefs of Staff official said he was found collapsed in a pile of fallen leaves and recovered by three South Korean soldiers crawling on their stomachs to his position.
He received gunshot wounds to the shoulder and elbow from North Korean forces while defecting. It is located inside the 4-kilometer-wide (2 1/2-mile-wide) Demilitarized Zone, which forms the de facto border between the Koreas since the Korean War.More news: Testimony: Fox Sports involved in soccer bribes
North Korean military personnel are reportedly preparing for their winter training exercises as three United States aircraft carriers lurk near the Korean Peninsula in an unprecedented show of force by Washington's navy.
Suh said the South had also informed the North on Monday of the soldier and his treatment, via loudspeakers on the border. Jointly controlled by the American-led U.N. Command and North Korea, the DMZ is guarded on both sides by hundreds of thousands of combat-ready troops, razor-wire fences and tank traps. In 1998, a North Korean solider fled to South Korea via Panmunjom.
The North Korean ambassador accused the council of "turning a blind eye to the nuclear war exercises of the United States who is hell bent on bringing a catastrophic disaster to humanity".More news: Blake Shelton named People's 2017 'Sexiest Man Alive'
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