Seoul says North Korean mines buried south of the line wounded three soldiers

South Korea's military said on Monday that land mines planted by North Korea, and buried south of the Military Demarcation Line, caused the 21 September blast inside the Demilitarized Zone that wounded three South Korean soldiers.

Lieutenant General Kwon Dae-won, vice chairman of the Joint Chiefs of Staff, gave the finding at the defence ministry in Yongsan. He said a joint investigation with the United Nations Command had confirmed the preliminary conclusion. Fragments taken from the injured soldiers matched North Korean plastic antipersonnel mines previously recovered from the Imjin River: a brown casing with a lattice pattern on the cover.

Two of the soldiers suffered critical injuries to their ankles. A third was hurt lightly. The mines that detonated were buried about 3 to 10 centimetres underground, Kwon said. That depth is the detail that separates this blast from the mines that wash south in floods and turn up on the surface. A mine under a few centimetres of soil was put there.

The Joint Chiefs said the South removed the minefield south of the line at about 12:51 p.m. on Monday, the first clearance operation staged in response to the blast. The military released footage of black smoke and an explosion, and described the work as aimed at North Korean mine-laying sites that the UN Command had verified.

North Korean mines are a known hazard south of the line because floods carry them across. The Monday finding rejects that explanation for the 21 September blast. Burial depth, casing match and the UN Command's joint result are the three points the South put on the record. Pyongyang had not, in the Seoul account, accepted the finding.

The blast site sits inside the Demilitarized Zone, the buffer that has divided the peninsula since the 1953 armistice. The Military Demarcation Line runs through it. Planting a mine south of that line is a crossing, even if no soldier walks across. Seoul's response on Monday was a clearance, not a shot. The operation still puts South Korean troops on ground the investigation now treats as a North Korean mine belt.

Kwon's briefing is the final military result, not a prosecutor's charge. The UN Command's role matters because the armistice machinery, not a bilateral hotline alone, is what certifies activity inside the zone. A UNC-verified minefield gives Seoul a document it can take to the commission that supervises the armistice.

The injury pattern is specific. Ankle wounds from a buried antipersonnel mine are what that class of weapon is built to produce. The third soldier's minor injuries fit a blast at close range rather than a wide fragmentation strike. None of the three was reported dead.

Monday's clearance at 12:51 p.m. is the operational half of the announcement. Identifying a mine and leaving it in the ground would have kept the patrol route closed. Blowing the field is how the South reopened it. The footage is the public proof that the work happened the same day as the briefing.

The open question is whether the mines were a one-time plant or part of a wider belt south of the line. Kwon tied the fragments to a known North Korean type and the burial to a deliberate plant. He did not give a count of mines still in the ground beyond the field cleared on Monday. Patrol routes inside the zone now depend on that count.