A senior South Korean presidential official on Thursday, 25 September vowed that a prompt and thorough investigation into the recent Demilitarised Zone (DMZ) explosions is already under way, following an incident on Monday in which three South Korean soldiers were injured by suspected mine blasts south of the Military Demarcation Line (MDL) on the western inter-Korean border.

Key Developments

The official made the remarks while accompanying South Korean President Lee Jae Myung on his ongoing state visit to Mexico City. Speaking to reporters, the official confirmed that forensic analysis of collected mine fragments is under way to determine whether they are of South Korean or North Korean origin.

'An objective, prompt and thorough investigation is under way,' the official told reporters. The probe is being coordinated with the United Nations Command (UNC), given that the explosion site lies on a new reconnaissance route — making it hazardous to access.

What the Investigation Must Determine

'A thorough fact-finding (probe) is needed to determine whether they were mines, and if they were mines, what kinds of mines they were, as well as whether they were buried by North Korea, and if not, what happened,' the official said. The official ruled out any cover-up, adding: 'Although dangerous, we will (investigate) promptly to announce the results.'

Critically, authorities have not yet confirmed whether the blast occurred at a specific site where North Korea is already suspected of illegally laying mines across the border. Difficult terrain within the buffer zone has also hampered visual confirmation, and clear footage of the explosion site has reportedly not yet been obtained.

New Defence Minister Takes a Firm Stance

On Tuesday, South Korea's newly inaugurated Defence Minister Kang Shin-chul issued a direct warning to Pyongyang, urging the North to halt its ongoing border-hardening measures along the inter-Korean boundary. His remarks came during a press availability following his inauguration ceremony.

'(North Korea) must cease its border fortification. Of course, we need to speak out,' Kang said. He also pushed back against suggestions that Seoul treads carefully around the North: 'You keep bringing up that we walk on eggshells when it comes to North Korea, but we do not.'

Kang acknowledged the explosion could be a consequence of North Korea's broader border-hardening campaign, including fencing and suspected mine-laying activities on the South Korean side of the DMZ. 'There are secondary effects that stem from North Korea's border-hardening, and this (explosion) could be one of them,' he said.

Investigation Challenges

Kang noted a key investigative uncertainty: whether the area where personnel entered, the specific patrol route, and the confirmed blast location all correspond. 'The problem is that we cannot confirm this at this point. That is precisely what the investigation must determine,' he told reporters. The injured soldiers' direct testimony is also reportedly difficult to obtain given their current condition, further complicating the probe.

What Comes Next

The investigation, being conducted in close coordination with the United Nations Command, is expected to conclude with a formal announcement once forensic analysis of the mine fragments is complete. The outcome could have significant implications for inter-Korean relations, especially amid growing speculation that North Korea may have planted mines illegally on the southern side of the border — a charge Pyongyang has not yet publicly addressed. Analysts will be watching whether Seoul formally attributes the blast to the North, which would likely trigger a sharper diplomatic or military response.