Three South Korean soldiers were wounded by landmine blasts in the Demilitarized Zone on September 21, and a joint on-site investigation by the South Korean military and the UN Command found an active North Korean anti-personnel mine south of the Military Demarcation Line [6][9][10]. South Korea's Joint Chiefs of Staff assessed that North Korean mines were "highly likely" the cause [1][7], and Defense Minister Kang Shin-chul told a parliamentary hearing that Pyongyang appeared to have planted mines at several locations south of the MDL during its border-hardening works, calling the incident a clear violation of the 1953 Armistice Agreement [1][6][22]. Kang stated that the discovered mine appeared planted rather than drifted, saying "Es sieht nicht danach aus, dass sie verdriftet ist" (It does not look as though it drifted) [22].
The JCS operations chief, Kang Hyun-woo, demanded that North Korea apologize and immediately halt its border fortification, calling the mine blast "a blatant violation of the Armistice Agreement" and stating that "all responsibility for any future situation lies entirely with North Korea" [8][18]. The JCS said the blast undermines the spirit of existing inter-Korean agreements and that the border fortification must be halted immediately [8]. North Korea has strengthened the heavily fortified border since 2024 [21].
Kim Yo-jong rejected Seoul's findings as a "farce" and denied that North Korean troops had crossed the Military Demarcation Line [2][3][6][19]. In a statement carried by KCNA, Kim accused South Korean military officials of fabricating results for political and military provocation and compared the incident to the 2015 wooden-box mine case, dismissing it as a "self-staged farce" [3][13]. Kim described the border barrier construction as a pure exercise of sovereignty and warned: "If the ROK military gangsters fire at our soldiers carrying on the permanent project for the southern border, not warning shots, our border units will take immediate and merciless retaliate attack" [6][7]. She also announced that Pyongyang had decided to strengthen tactical counterattack means near the DMZ facing South Korea's 21st Infantry Division [3].
The UN Command, which conducted the joint investigation with the South Korean military, determined that "an Armistice Agreement violation occurred" after identifying an active North Korean anti-personnel mine on the ROK side of the MDL [2][9]. The UNC said it is addressing the violation through established armistice mechanisms but declined to name which side bears responsibility — a stance distinct from Seoul's explicit attribution and from the UNC's own handling of the 2015 wooden-box mine case, in which it explicitly assigned blame [9]. UNC spokeswoman Choi Min-jung said the command had no further comment while the incident remains under investigation [10].
Within South Korea, the response split along political lines. The National Assembly National Defense Committee deadlocked over a resolution condemning North Korea, with the ruling Democratic Party and the opposition People Power Party failing to agree [11]. People Power Party floor manager Lim Jong-deuk said the resolution must secure an apology from North Korea and a pledge to prevent recurrence, while party lawmaker Han Ki-ho called for halting humanitarian aid, arguing it is contradictory to provide aid while condemning the North [11]. Democratic Party floor manager Kim Byung-ju countered that no aid to the North is currently being pursued and that much of the opposition's demands were already reflected in the draft [11]. Reform Party lawmaker Cheon Ha-ram questioned whether the president's political schedule was prioritized over national security, citing the delay in announcing the North Korean mine presumption [11]. A JoongAng Ilbo editorial criticized the military's slow response, noting the site investigation was initially planned for the eighth day and that the unexploded mine has not been recovered [17].
The Unification Ministry said it would study necessary measures based on the final investigation results, and the Defense Ministry's deputy spokesperson Lee Kyung-ho said concrete military response options would be judged after analyzing the final findings [15]. Doo Jin-ho, a visiting research fellow at Kyungnam University's Institute for Far Eastern Studies, suggested consulting the UNC to push thermal observation devices forward into MDL surveillance blind spots and to use ground and aerial unmanned surveillance assets [14]. An analytical column noted that restarting anti-North loudspeaker broadcasts would impose political pressure on President Lee Jae-myung's engagement policy [16]. Lee has sought dialogue with Pyongyang, recently proposing a swap in which the United States would lift sanctions and North Korea would freeze its nuclear program, and in his UN General Assembly address said South Korea would create conditions for dialogue on ending the Korean War and moving toward a peace mechanism [16][22]. North Korea has not responded to the proposal [22].
Lim Eul-chul, a professor at Kyungnam University's Institute for Far Eastern Studies, said Kim Yo-jong's remarks appear designed to create a justification for future retaliation against South Korean warning shots or broadcasts, arguing that "North Korea is accumulating a narrative that any future clash is not the result of its own actions but a response to South Korean provocations" [2][4].
The blast site sits within a DMZ that franceinfo reports is estimated to contain roughly 800,000 mines across its four-kilometer width, with the two Koreas remaining technically at war since the 1953 armistice [20]. The wounded included a 25th Infantry Division search battalion commander who lost an ankle in a second blast while rescuing a subordinate during a terrain-clearing mission; his first words after surgery were "다른 부대원들은 괜찮습니까" (Are the other unit members okay?) [12]. Kang visited the wounded soldiers at the capital hospital and called them true heroes for being injured while trying to save comrades [12].
The JCS vice chairman said preliminary findings indicate the mines likely belonged to North Korea and that if responsibility is confirmed, the military will take "appropriate and corresponding measures" [10][16]. The investigation's final findings are pending additional analyses [7][9].