South Korea details evidence linking DMZ mine blasts to North Korean mines

South Korea’s military said on October 5 that North Korean mines planted south of the Military Demarcation Line caused two blasts during a September 21 operation in the Demilitarized Zone, injuring three South Korean soldiers, two seriously. The finding led Seoul to clear mines at the blast site and demand an apology from North Korea, which has denied responsibility, according to The Associated Press. The dispute concerns both the soldiers’ safety and whether mines were placed across the line separating the two forces.

What the joint investigation found at the DMZ blast site

The final finding followed a September 26–29 site investigation conducted with the United Nations Command and forensic results received on October 2, according to South Korea’s October 5 defense briefing. Investigators said GPS measurements put the two explosion points and a third location where a mine was found roughly 10 metres south of the Military Demarcation Line. The briefing said another North Korean resin-cased antipersonnel mine was discovered near the blast site on September 29.

South Korea’s military cited several kinds of evidence for its assessment. Its briefing said tests detected TNT, brown material and thermosetting resin. Investigators compared fragments recovered from injured personnel with a previously recovered North Korean resin-cased mine and reported matching material. Soldiers had described one mine as buried about 5–10 centimetres deep; the mine found during the later site investigation was about 3 centimetres underground.

The United Nations Command assessed that the mine had been deliberately placed and installed more than 12 months earlier, the South Korean briefing said. South Korea concluded that North Korean troops had laid the mines during border fortification work and that their placement south of the line violated the armistice. Those are the investigators’ findings: the public briefing describes the tests and measurements but does not supply the complete forensic report or underlying GPS data for independent examination.

How South Korea responded after the finding

South Korea called on North Korea to apologize to the injured soldiers and remove mines it says were placed across the demarcation line. The Associated Press reported that Seoul did not announce substantial punitive steps when it released the final finding. AP also reported that North Korea denied responsibility for the September 21 blasts and threatened retaliation if provoked over the case. The available accounts do not describe a North Korean technical counter-investigation, leaving the two governments’ positions in direct conflict.

What the military chief said on October 8

At a parliamentary audit on October 8, Joint Chiefs of Staff Chairman Gen. Jin Yong-sung said he had regarded the blast as a North Korean ‘provocation’ throughout. Yonhap reported that he acknowledged he had not paid close attention to the omission of that word from the military’s October 5 announcement. His remarks clarified how he characterised the incident, but they did not set out a further response.

Jin called the completed mine-removal operation significant and said he would continue reviewing necessary measures, without specifying what they might be. Yonhap also reported a military pledge to strengthen readiness and reduce surveillance blind spots. As of Jin’s October 8 remarks, the announced physical action at the blast site was the clearance operation; any additional measures remained undefined.

Why the border setting matters

The mine case comes amid wider fortification work along the inter-Korean border. AP reported that North Korea has added mines, fences and anti-tank barriers in recent years. It also reported South Korean military counts of 17 alleged crossings of the Military Demarcation Line by North Korean troops in 2025 and 50 in 2026 during that work. Those counts are allegations about border activity, not separate proof of who placed the mines involved in the September blasts.

A 2015 border mine incident blamed on North Korea pushed the two sides close to armed conflict, AP reported. That precedent helps explain why both the location of the mines and the language used to describe the blasts draw scrutiny; it does not establish the cause of this incident. NewsJaws previously covered South Korea’s call for an apology after the soldiers were injured. The October 5 final finding added the joint site measurements and forensic assessment, followed by mine clearance and Jin’s October 8 account of how the military viewed its response.