Seoul moves to formally cite North Korea for armistice breaches over DMZ border incursions

South Korea's Ministry of National Defense said on Wednesday, 7 October, that it will investigate North Korean incursions across the Military Demarcation Line jointly with the United Nations Command, formally classify them as violations of the 1953 Armistice Agreement and notify Pyongyang. The plan was set out in a briefing report for the National Assembly's National Defense Committee ahead of its annual audit of the ministry.

Through that notification, the ministry said it would press the North to stop the violations and return the Demilitarized Zone to its original state. It also said it would coordinate with the UN Command, which is responsible for managing the armistice, against North Korean moves to shrink or dismantle the buffer zone the agreement created.

Follow-up to the September mine blast

The step follows the 21 September explosion on the western front that wounded three South Korean soldiers, two of them seriously. According to the briefing, a joint military task force and the UN Command carried out an on-site investigation from 26 to 29 September and, drawing on National Forensic Service analysis and testimony from troops, concluded the blast was caused by a plastic anti-personnel mine laid by North Korean forces south of the demarcation line.

The ministry said it would run further joint investigations with the UN Command in other areas where mine-laying incursions are suspected and would continue clearing North Korean mines on the southern side of the line. It pledged medical and recovery support for the wounded soldiers and said it would consider honours and personnel measures that recognise their sacrifice.

Posture along the border

The briefing said North Korea has been laying minefields and building fences near the demarcation line since April 2024 while reinforcing border units with 240 mm and 600 mm multiple rocket launchers, self-propelled artillery and drones. In response, the ministry said it would tighten surveillance and response postures to keep the operational initiative in the DMZ, update targets in border areas to strengthen counter-battery capability, and respond firmly under its operational procedures if the North crosses the line.

Seoul also repeated its push for inter-Korean military talks to prevent accidental clashes, align the baselines each side uses for the demarcation line and restore military communication lines. Only about 200 of the 1,292 marker posts installed along the line in 1953 can still be identified, Yonhap reported.

Audit and wider agenda

At Wednesday's audit, lawmakers pressed the military on when it first detected signs of the mine-laying, what safety measures were in place during clearance operations, how it responded initially and how it plans to remove further mines, the Herald Business reported. A day earlier, North Korea's Foreign Ministry had again rejected the South's findings and threatened an immediate response if South Korean troops entered territory it claims.

Defence Minister Kang Shin-chul told the committee that winning without fighting was the best strategy and said the military would build up independent capabilities through the transfer of wartime operational control. The ministry said it aims to verify full operational capability of the Future Combined Forces Command at this year's Security Consultative Meeting to set a transfer timeline.

Formally lodging armistice violations through the UN Command gives Seoul a legal record of the incursions, but it does not by itself compel Pyongyang to remove its mines or stop fortification work near the line.