South Korea clears DMZ minefield after investigation finds North Korea behind blast that wounded three soldiers

South Korea's military began clearing a North Korean minefield located south of the military demarcation line (MDL), after concluding that the North had planted the mines that wounded three South Korean soldiers in the demilitarized zone (DMZ) last month.

Monday's operation, the military's first concrete response to the Sept. 21 blast, followed a joint on-site investigation with the United Nations Command (UNC).

"Based on the results of the joint investigation with the UNC and scientific evidence, we have made a final determination that our soldiers carrying out normal DMZ operations south of the MDL were seriously wounded by a plastic antipersonnel mine North Korea laid south of the MDL under the pretext of its so-called border fortification work," Lt. Gen. Kwon Dae-won, vice chairman of the Joint Chiefs of Staff, said during a briefing at the Ministry of National Defense in Yongsan District, central Seoul.

The conclusion rested on the military's and the UNC's assessments of three questions: where the blasts occurred, whose mine it was and whether it had been deliberately planted, according to Kwon. 

The sites of the first and second explosions, and a North Korean plastic antipersonnel mine found at the scene last Tuesday, all lay south of the MDL.

"Using GPS, the UNC and the joint investigation team ultimately confirmed that the three sites were about 10 meters [33 feet] south of the MDL and determined that this violated the Armistice Agreement," Kwon said.

Tests by the National Forensic Service on the wounded soldiers' equipment found TNT, thermosetting resin and a brown foreign substance, evidence pointing to a North Korean mine. Fragments taken from the soldiers' bodies also matched a North Korean plastic antipersonnel mine previously recovered from the Imjin River.

The military also concluded that the mines had been planted rather than swept in. Soldiers at the scene testified that the mine they saw was buried 5 to 10 centimeters (2 to 4 inches) deep, and the mine found last Tuesday had been buried about 3 centimeters down.

"The UNC also assessed that the mines had been deliberately placed and that they were laid about 12 months ago," Kwon said. "Considering the spacing between the mine actually found and the craters left by the exploded mines, as well as the distance between rows, we judged them to be typical North Korean mines that had been laid, not mines that had drifted."

The military destroyed the minefield at around 12:51 p.m. on Monday and released footage of the operation showing an explosion and black smoke.

"The purpose of this operation is to remove the minefield North Korea laid south of the MDL in violation of the Armistice Agreement," Kwon said. "It was carried out safely in close coordination with the UNC, in compliance with the armistice and with measures in place to prevent accidental clashes."

The Armistice Agreement that ended the 1950-53 Korean War bans hostile acts "within, from or against" the DMZ and prohibits crossing the MDL without authorization from the Military Armistice Commission.

The military will continue clearing mines if North Korea does not remove those it laid south of the MDL voluntarily.

"We strongly urge North Korea, even now, to offer a sincere apology to our soldiers injured in this mine explosion and to immediately remove the mines it laid in violation of the Armistice Agreement," Kwon said.

The UNC also declared the blast an armistice violation last Wednesday. 

North Korea has been fortifying the border since April 2024, reinforcing barbed-wire fences, planting mines and building anti-tank barriers along the MDL.

Pyongyang has rejected the findings. In a statement last Tuesday, Kim Yo-jong, the sister of leader Kim Jong-un, called the incident a "farce of their own making."

She warned of "immediate and merciless" retaliation if South Korean troops opened fire on North Korean soldiers. In another statement on Friday, she declared, "The enemy is the enemy after all."

The government had said it would decide the extent of its response once the military released its final findings.

BY SHIN HYE-YEON, CHO YONG-JUN [[email protected]]