Kim Yo-jong Dismisses Seoul’s DMZ Mine Claim, Warns of ‘Merciless’ Retaliation

North Korea on Wednesday denied involvement in a recent explosion along the inter-Korean border, dismissed South Korea’s findings as false and warned that it would respond “immediately and mercilessly” if South Korean troops fire on North Korean soldiers working near the border.

The unusually rapid warning came from Kim Yo-jong, the influential sister of leader Kim Jong-un and a department director in the Workers’ Party Central Committee, after South Korea’s Joint Chiefs of Staff said North Korean mines were “highly likely” to have caused the Sept. 21 blast. Three South Korean soldiers were wounded, two of them seriously.

Analysts said Pyongyang’s military threat appeared aimed less at the western section of the Demilitarized Zone where the explosion occurred than at the eastern front, where North Korea has been building up border fortifications.

That shift in focus suggests North Korea may be trying both to deny responsibility for two consecutive blasts and to shield its ongoing construction work along the border, while discouraging Seoul from actions that could interfere with it, experts said.

In an English statement carried by the Korean Central News Agency, Kim accused the South Korean military of fabricating “groundless results” to justify political and military provocations against North Korea.

She said North Korean troops carrying out what Pyongyang describes as the permanent fortification of its southern border had “never crossed the border,” and accused South Korea of threatening them with warning broadcasts and warning shots.

Kim said that if South Korean soldiers fired at North Korean troops working on the border project, rather than firing warning shots, North Korea’s border units would carry out an “immediate and merciless” retaliatory attack.

She added that the North Korean military had decided to strengthen “tactical counterattack means” directed at South Korea’s 21st Infantry Division, part of the III Corps, and had issued counteraction guidelines to border defense units.

However, the 21st Infantry Division is deployed along the eastern front, while the Sept. 21 explosion took place in the western DMZ, an area associated with South Korea’s 25th Infantry Division.

Hong Min, a senior researcher at the Korea Institute for National Unification, said the geographic mismatch was significant because the sector facing the 21st Infantry Division is a central focus of North Korea’s border reinforcement effort.

According to Hong, North Korea’s more immediate concern may be preventing South Korea’s response to the mine explosion from disrupting its construction work or endangering personnel there.

“The incident is in the west, while the warning is directed toward the east,” Hong said in his analysis of Kim’s statement.

Since 2024, Pyongyang has reinforced barbed wire, laid mines and installed anti-tank barriers along the Military Demarcation Line as part of a push to physically break its links with the South.

Lim Eul-chul, a professor at Kyungnam University’s Institute for Far Eastern Studies, said North Korea appears determined to cast South Korean warning shots and other border actions as interference with what it considers legitimate exercises of sovereignty.

He said such framing could provide Pyongyang with a pre-existing justification for retaliation if a miscalculation or exchange of live fire occurs along the heavily fortified frontier.

Lim added that the warning may also be meant to pressure South Korean commanders and policymakers into avoiding measures such as broadcasts or warning shots near North Korean construction sites.

The exchange of sharp rhetoric came as the South Korean military issued its first official message directly addressed to Pyongyang over the Sept. 21 explosion.

On Wednesday, the Joint Chiefs of Staff demanded that North Korea apologize and take “responsible measures,” and called on Pyongyang to stop border activities that raise military tensions.

Lt. Gen. Kang Hyun-woo, chief director of operations at the JCS, said the explosion was a “blatant violation” of the Armistice Agreement and undermined the spirit of existing inter-Korean accords, insisting that it must stop immediately.

Kang also demanded that North Korea cease activities heightening tensions on the Korean Peninsula, including what Seoul calls “border fortification,” and warned that Pyongyang would bear full responsibility for any future consequences.

South Korean forces said a preliminary investigation found that resin antipersonnel mines deliberately placed south of the MDL were highly likely to have caused the explosion.

The United Nations Command separately concluded that the explosion violated the Armistice Agreement, and a joint investigation with South Korean forces identified an active North Korean mine south of the MDL.

Hong said Kim’s intervention, coming just one day after the JCS released preliminary findings, moved the dispute beyond a working-level military issue and reflected Pyongyang’s increasingly assertive stance.

At the same time, he noted, Kim linked retaliation to live fire against North Korean troops or to what Pyongyang regards as an infringement of its territory, rather than identifying warning broadcasts or warning shots as triggers. That distinction could indicate an attempt to set a retaliation threshold while leaving room to manage escalation.

Lim, however, warned that the reinforcement of tactical counterattack means near the border could raise the risk of an accidental clash. He called for intensified surveillance, carefully managed rules of engagement and efforts to restore inter-Korean military communication channels to prevent unintended escalation.