SEOUL — North Korea's top foreign policy official, Kim Yo Jong, on Wednesday dismissed South Korean accusations that Pyongyang planted landmines that injured three South Korean soldiers last week. Kim Yo Jong, the powerful sister of leader Kim Jong Un, also threatened retaliation if South Korean forces fire on North Korean troops engaged in border fortification.

Three South Korean soldiers sustained injuries in two separate explosions on Sept. 21 near the military demarcation line in the western section of the Demilitarized Zone, the heavily fortified buffer separating the two nations.

South Korea's military announced its preliminary assessment on Monday, concluding the explosions were caused by North Korean mines, following a joint inspection with the U.S.-led United Nations Command. During a follow-up inspection on Tuesday, South Korean and U.N. investigators discovered an additional North Korean mine.

The U.N. Command stated that North Korea violated the armistice agreement that concluded the 1950-53 Korean War. The armistice prohibits hostile acts "within, from, or against" the DMZ and bans military or civilian personnel from crossing the military demarcation line without authorization from the armistice commission. The U.N. Command said it was addressing the violation through established mechanisms.

Kim Yo Jong labeled the South Korean assessment a "conspiratorial farce" and accused Seoul of fabricating claims to create a pretext for provocation. She said North Korean troops conducting front-line fortification work "have never crossed the border."

Kang Hyunwoo, director of operations for the South Korean Joint Chiefs of Staff, called on North Korea to apologize for the blasts and implement measures to prevent recurrence. South Korean Defense Minister Kang Shin-chul indicated that Seoul would consider "corresponding measures" if an investigation definitively confirms North Korea's responsibility.

The incident further strains relations between the two Koreas, which lack functioning military hotlines or other emergency communication channels. In recent years, North Korea has intensified border fortifications, adding mines, anti-tank barriers and other structures. The dispute complicates Seoul's diplomatic efforts to revive U.S.–North Korea talks.