Troops saw object resembling box mine near DMZ blast site, JCS says

Soldiers present at the scene of a suspected mine explosion in the Demilitarized Zone said they saw an object near the blast point that resembled a box mine, the military confirmed Monday. However, some accounts described the material as appearing to be plastic, and others suggested the device may have been a different type of mine altogether. The military said it would determine the type of mine by combining the findings of an on-site investigation with results from the National Forensic Service.

Maj. Gen. Hwang Ju-bong, director of operations at the Joint Chiefs of Staff, told a regular Defense Ministry briefing Monday that the accounts were drawn from multiple soldiers, not just one. "Some statements described the shape as similar to a box mine and the material as appearing to be plastic, while others suggested a different type of mine," he said.

He added that several types of mines share a similar shape and color to the box mine. "I will explain once we have made a clear confirmation on the ground," he said.

On the location of the sighting, Hwang said it was "near the blast point," but stressed that the precise range of "near" could only be determined after visiting the scene. He deferred questions about how many soldiers saw the object, whether it was exposed above the surface or buried, and whether any unexploded mines were present, saying those details "require confirmation."

"We cannot conclude that what person A saw and what person B saw were the same thing," Hwang said. "We need to re-detect and cross-reference on the ground."

He also explained why the military had said at a background briefing Wednesday that it was "not in a position to say" which side's mine the soldiers thought they had seen — the accounts had been inconsistent. The military acknowledged some credibility in the testimonies, noting that soldiers are trained on the shape and material characteristics of both enemy and friendly mines before being deployed to DMZ operations. North Korea's box mine, the PMD-57, is originally made with a wooden casing.

On the analysis to determine whether the explosive was tetryl — used in the M14 antipersonnel mine — or TNT, which is used in the box mine, Hwang said the clothing of the personnel involved had been submitted to the National Forensic Service. "Whether it is tetryl or TNT will be confirmed when the results come in," he said. He said the military was also "investigating" observations that the injuries appeared more severe than would be expected given that the soldiers were wearing mine-protective overshoes.

On whether body cameras recorded audio, and on video and audio materials from the time of the incident, Hwang said the task force was reviewing video, audio and other elements together and that it would not be appropriate to address any single item in isolation. He said the findings would be explained when the investigation results are announced.

The military also clarified the term "unconfirmed minefield," used for the first time in a Sunday announcement. A JCS official said the area was not one where South Korean forces had operated continuously since 1953. "There will be mines laid by our sunbae comrades for defensive purposes, and there have been various changes since then, but we cannot account for everything that is recorded and unrecorded — that is why we called it an unconfirmed area," the official said.

Hwang described the area as "a new zone with no separate search route, a buffer area that has not been visited for decades, which is why mine-clearing had to come first." Asked whether it was more likely that the explosion was caused by a mine laid in the past, he said multiple factors had to be considered and that nothing could be specified or concluded.

The military confirmed that terrain changes suspected to indicate North Korean mine-laying were first observed in the second half of last year. Hwang said that after the observation, forces had responded firmly in accordance with operational procedures whenever the military demarcation line was crossed nearby. He added that several locations near the MDL had been roughly identified and reported to the United Nations Command, and that the division, corps, Ground Operations Command and JCS were all in agreement on those locations.

He said the area was not fully visible through guard post and general outpost surveillance equipment and had been confirmed using satellite and other imagery. Asked whether the blind spot was related to guard post withdrawals under the Sept. 19 inter-Korean military agreement, he said it was "completely unrelated" and that the guard posts in that area were operating normally. On the reporting chain and its limitations, he said only that reports were being made through both the command and situation channels, declining to elaborate on operational procedures.

A JCS official said the PRS-20K mine detector used during the operation was understood to be capable of detecting non-metallic objects, and that the range covered by the detector on the ground would be confirmed during the on-site investigation. If an explosion occurred despite the detector's capabilities, the scope of detection and the procedures followed are expected to become central issues in the probe.

Asked whether the military had considered deploying unmanned equipment such as drones or robots before entering the hazardous area, Hwang said the UNC had requested a direct on-site inspection, which meant clearing a search route had to come first. "Such equipment was not discussed at the outset," he said, though he added that robots had been used in some areas and that he would explain further at a later time.

On the possibility that evidence had been damaged by rain during the chuseok holiday period, a JCS official said roughly 4 to 5 millimeters of rain had fallen — less than forecast — and that any loss of evidence was assessed to be minimal.

The investigation team's failure to reach the blast origin Sunday was attributed to the weight of protective gear. "The protective equipment is quite heavy and difficult to move in, which is why it took more time," Hwang said. Asked why the investigation was slower than on Sept. 21 despite using the same equipment, he said the situation had changed: "At that time, the enemy did not know we were detecting, but now virtually the entire country can know in real time." He said that shift in situational assessment had made the operation more cautious, and also cited the increased number of personnel deployed and the expanded roles of each unit.

On whether delays were caused by the UNC not being ready, Hwang said high-level communication had begun on the day of the accident, which had allowed helicopters to enter faster than usual. "We have been working together from the first day basic investigations began," he said. Asked whether there were differences between South Korea, North Korea and the UNC over the MDL boundary in the area, he declined to answer, citing operational security requirements.

The Defense Ministry said it would carefully review necessary follow-up measures, including improvements to operational methods, based on the investigation results.

The accident occurred at around 10:50 a.m. on Sept. 21 during a search-route clearing operation in an area near the MDL in Paju, Gyeonggi Province, under the jurisdiction of the 25th Division. Two suspected mine explosions took place in succession, leaving two soldiers — including the search battalion commander — seriously injured and one with minor injuries.