Seoul, Oct 5 (IANS): North Korea-planted land mines exploded and injured three South Korean soldiers inside the Demilitarised Zone (DMZ) last month, South Korea’s military concluded Monday, saying it conducted a mine-clearing operation at the blast site in response.
The South’s military announced the final result of its joint investigation with the U.N. Command (UNC) into the Sept. 21 mine blast, confirming its preliminary findings that resin antipersonnel mines deliberately planted by Pyongyang south of the Military Demarcation Line (MDL) were the cause of the blast.
Two South Korean troops suffered critical injuries to their ankles, while a third sustained minor injuries, Yonhap News Agency reported.
The mines involved in the recent blasts contained trinitrotoluene (TNT) and thermosetting resin components consistent with North Korean mines, Lt. Gen. Kwon Dae-won, vice chairman of the South’s Joint Chiefs of Staff (JCS), said in a press briefing.
Fragments recovered from the injured soldiers were identical to the North Korean plastic antipersonnel mines previously recovered from the Imjin River — featuring a brown casing with a lattice pattern on the cover, he said.
North Korean mines are often found south of the MDL after they are swept away to south of the inter-Korean border in floods, but the ones that triggered the recent blast were “buried about 3 to 10 centimetres underground,” Kwon said, citing the joint investigation result.
“The UNC has also found that those mines were intentionally placed, and it estimated the installation occurred roughly 12 months prior,” he said.
The military said GPS measurements showed that the two blast sites and the site where an additional mine was discovered were all located about 10 meters south of the MDL.
The JCS said it removed the minefield south of the MDL at around 12:51 p.m. Monday, in its first operation in response to the mine blast.
The military released footage of the operation showing black smoke billowing and the booming sound of an explosion, describing the mission as an “effective” operation on the North’s mine-laying sites verified by the UNC.
The military vowed to continue mine-removal operations in the area if North Korea refuses to voluntarily remove its mines planted there.
“The military strongly calls on North Korea to offer a sincere apology to the South Korean soldiers injured in the mine blast and immediately remove the mines it planted in violation of the Armistice Agreement,” Kwon said.
The Armistice Agreement, which ended the 1950-53 Korean War, prohibits hostile acts “within, from or against” the DMZ, the buffer zone covering the MDL. It also bans border crossings unless authorised by the Military Armistice Commission.
North Korea has been fortifying the inter-Korean border since April 2024 by reinforcing barbed-wire fences, planting mines and erecting anti-tank barriers along the MDL after its leader Kim Jong-un declared inter-Korean ties to be those between “two states hostile to each other” the previous year.
The JCS said it has detected increasing North Korean activity along the MDL since March 2025, estimating that as many as 7,000 troops may have been mobilised daily to clear land for mine-laying and fencing, especially along the eastern front.
Since the North began fortifying the border, its border intrusions to the south of the MDL have spiked to more than 50 cases this year, from nine in 2024 and 17 in 2025, the JCS said.
North Korea has denied responsibility for the recent explosions inside the DMZ.
Kim Yo-jong, the powerful sister of leader Kim, has dismissed Seoul’s findings as a fabrication and warned of retaliation if South Korea takes corresponding action.
