Military says N. Korea 'highly likely' behind DMZ blast, vows 'corresponding measures'

Yang Jin-hyeok, operations chief of the Joint Chiefs of Staff, briefs reporters at South Korea's Ministry of National Defense in Yongsan-gu, Seoul, on Monday on the suspected land mine explosion in the Demilitarized Zone. [Yonhap]

South Korea's military said Monday that a North Korean land mine is "highly likely" the cause of an explosion in the western DMZ on Sept. 21, warning that if the mine is confirmed to have been planted by the North, it will take "corresponding measures."

Kwon Dae-won, vice chairman of the Joint Chiefs of Staff and head of the joint field investigation TF on the DMZ mine explosion, held a briefing Monday and said the military had determined that "the cause of this mine explosion is highly likely to be a North Korean military mine."

Kwon said interim findings indicated the explosion was not caused by a South Korean mine, citing the shape of the blast crater and flame pattern observed at the scene, witness accounts, and the severity of injuries sustained by the affected soldiers.

According to Kwon, there are no records of South Korean mines being planted in the area where the explosion occurred, and traces of North Korean mine-laying activity in the vicinity were discovered in September 2025.

Initial forensic analysis by the National Forensic Service — commissioned by the military — detected TNT and brown-colored foreign substances on one ballistic helmet and two bulletproof vests belonging to the injured soldiers. The TNT traces were found on torn and scorched portions of the gear.

The National Forensic Service delivered the initial forensic results on the injured soldiers' equipment to the military at around 4 p.m. Monday.

North Korean wooden-box mines typically contain about 220 grams of TNT explosive. No metal fragments — which South Korean mines commonly produce in large quantities when they detonate — were found at the scene.

Yang Jin-hyeok, JCS operations chief, said: "TNT was used as the explosive charge in the object that caused the blast, but given the absence of metal fragments, the presence only of brown foreign material, and the relatively small lethal radius, this was not a South Korean mine — it is highly likely to be a North Korean military mine."

Witness accounts gathered during the investigation also indicated that a brown North Korean plastic anti-personnel mine was found approximately 1 meter from the site of the first of the two explosions. An engineer unit reportedly identified a suspected mine buried 5 to 10 centimeters underground during a precision mine-detection sweep.

The object appears to be an anti-personnel mine with a smooth plastic casing, similar in shape to North Korean wooden-box mines.

Yang, citing engineer personnel accounts, said the object was described as "brown, square-shaped and made of smooth plastic," adding that "some personnel described it as red, others as brown, and some referred to it as a wooden-box mine."

"There are about three variants of the wooden-box mine, and the plastic anti-personnel mine has been in use by North Korea since 1969," Yang said, adding that some personnel assessed the object as bearing a strong visual resemblance to mines documented in North Korean military doctrine.

The military believes a total of three mines were present at the blast site: two detonated during the incident, and a third was found during the withdrawal, according to witness accounts.

The explosion occurred roughly 10 meters south of the MDL and approximately 10 meters from an area where terrain changes suggest North Korean forces recently planted mines.

South Korean forces and the United Nations Command conducted their second consecutive day of on-site investigation Sunday and Monday.

The second day of the investigation involved about 40 personnel, including the UNC Military Armistice Commission secretary and the 25th Division, which has jurisdiction over the area. The team reached a point 2 meters short of the second blast site but could not advance to the first blast origin, located another 2 meters beyond, as clearing a path to that point remained difficult.

Final investigation results are to be announced after a joint assessment with the UNC.

Kwon said the investigation did not conclude Monday and that additional sessions have been scheduled, adding that the mine reportedly found 1 meter from the blast site is to be confirmed in the final investigation.

"If the final investigation determines that our soldiers' injuries were caused by mines planted by North Korean forces, it means our troops — conducting normal DMZ operations south of the MDL — were wounded by North Korean mines," Kwon said.

He went on to say that "all responsibility for this lies with North Korea," adding that "our military will implement measures that are appropriate and corresponding."

With the military having publicly pledged "corresponding measures," a final confirmation of North Korean mine-laying would likely send shockwaves through inter-Korean relations. When North Korea deliberately planted wooden-box mines in 2015, South Korea responded by resuming loudspeaker propaganda broadcasts near the border for the first time in 11 years.

On what specific countermeasures might be taken, Yang said the JCS "will put all necessary options on the table — both military options at the JCS level and policy options at the Defense Ministry level — and make a judgment."

husn7@heraldcorp.com