On September 21, two mines exploded inside the Demilitarized Zone (DMZ) separating North and South Korea, injuring three South Korean soldiers, two of them seriously. Two weeks later, on October 5, the South Korean military announced its final determination that the explosion was caused by a plastic antipersonnel mine that North Korea had planted south of the Military Demarcation Line (MDL), the de facto border.
Deputy Chief of the South's Joint Chiefs of Staff Kwon Dae-won said the conclusion was based on a joint investigation with the United Nations Command (UNC) and scientific evidence. Both the UNC and South Korean military assessed that the mines had been buried for at least 12 months. South Korea said it had launched an operation to remove the mines by detonating them and called on North Korea to apologize and remove its mines in violation of the Armistice Agreement.
Pyongyang rejected the findings before the final announcement and refused an offer of talks on the border. The dispute places direct strain on President Lee Jae-myung's engagement-oriented policy toward North Korea.
The MDL divides the two Koreas, with the DMZ extending two kilometers on either side. The Armistice Agreement forbids hostile acts inside the DMZ and bars crossing the MDL without permission. The UNC holds authority to judge armistice violations. However, the border line has become difficult to read on the ground: only about 200 of the 1,292 original markers from 1953 remain intact, and Seoul's Defense Ministry has acknowledged that the baselines of the UNC and South Korea differ across roughly 60 percent of the border coordinates.
The explosion occurred during a South Korean operation to clear a path for a joint inspection with the UNC, intended to examine terrain changes near the MDL that officials suspected were signs of mine-laying by North Korea. The blast site lay about 10 meters south of the line.