Seoul says North Korean mines south of the MDL wounded its soldiers

South Korea's military said on Monday that North Korean anti-personnel mines, planted south of the Military Demarcation Line, caused the blast in the Demilitarised Zone that wounded its soldiers last month. The finding came from a joint investigation with the United Nations Command. Hours after the announcement, Seoul detonated the minefield.

Joint Chiefs vice-chairman Lieutenant General Kwon Dae-won said the explosion site was about 10 metres south of the MDL. He called that a violation of the Armistice Agreement. The device, he said, was a North Korean wooden-box anti-personnel mine, also described in the briefing as a resin or plastic anti-personnel mine. Two soldiers of the army's 25th Division suffered critical injuries to their ankles. A third had minor injuries. Yonhap dated the blast to 21 September. Other Korean reporting has used 24 September. The military's own briefing is the one that fixes the place: south of the line, inside the southern half of the DMZ, during what Seoul called a routine operation.

Kwon said the space between the mine that was found and the crater, and the distance between rows, did not look like a mine that had shifted in soil. It looked, he said, like a standard North Korean pattern that had been buried on purpose. A Joint Chiefs source said North Korean troops were seen watching the area when the blast was heard, and that the South detected no unusual movement at the time. Watching is not the same as a filmed laying party. It is what the South says it has.

The response on Monday was physical. At about 12.51pm the military cleared a North Korean minefield south of the MDL, using explosives. The Joint Chiefs said the UN Command had recognised the minefield itself as an armistice violation. Footage released with the briefing showed black smoke and the sound of the detonation. Seoul described the clearance as its first concrete action since the blast, and as an effective strike on mine-laying sites the UN Command had verified.

The armistice, signed in 1953, forbids either side from putting new fortifications and obstacles into the DMZ in the way a peacetime border fence is built. A wooden-box mine 10 metres on the wrong side of the MDL is a small object with a large legal label. It is also a soldier's injury: two wrecked ankles, one lighter wound, in a strip of ground where patrols are supposed to know the mine maps. If the mines were new, the maps were wrong because Pyongyang changed them. If they were old and unrecorded, the investigation's claim of a deliberate recent pattern is the point that has to hold.

Japan Times reporting on Tuesday said Seoul was preparing to force an apology from the North over the blast. An apology is a political demand. The military fact already on paper is the UN Command's joint finding and the crater 10 metres south of the line. What happens next is whether Pyongyang answers the clearance with its own detonation, or with silence. The soldiers' ankles will not wait on that answer.