An explosion in South Korea’s heavily fortified border area with North Korea injured three military officers on Monday, the country’s Defense Ministry said.
The blast occurred during an unspecified operation inside the Demilitarized Zone (DMZ), the buffer area separating the two Koreas. The ministry said the cause of the explosion was not immediately known.
Officials did not say whether the blast may have been caused by a land mine planted by North Korea. The North has increased border fortifications in recent months, including mines and anti-tank barriers, as tensions between the two countries have worsened.
Two of the injured officers were airlifted from the area by helicopter, while the third was taken out by land before being flown to a hospital, according to the ministry. All three are receiving treatment at a military hospital near Seoul.
The DMZ stretches about 248 kilometres and is 4 kilometres wide, making it one of the world’s most heavily armed borders. An estimated 2 million land mines are scattered in and around the area, which is also protected by barbed-wire fences, tank traps and troops from both sides.
The zone was established as part of the 1953 armistice that ended the 1950-53 Korean War. The two countries, however, have never signed a peace treaty.
Concerns have grown in South Korea over increased activity by North Korean troops near the Military Demarcation Line as Pyongyang strengthens its border defenses.
South Korea’s military has not officially confirmed media reports that North Korean troops crossed the demarcation line more than 20 times during front-line operations in August.
In April 2025, South Korean troops fired warning shots after about 10 North Korean soldiers crossed the line in the eastern section of the DMZ. The North Korean troops withdrew after South Korea issued audio warnings and fired the shots, with no clashes reported. In June 2024, North Korean troops crossed the border three times, prompting similar warning shots.
North Korean leader Kim Jong Un has in recent years suspended nearly all cooperation and diplomacy with South Korea and called Seoul his country’s most hostile enemy amid a broader deadlock in nuclear negotiations with the United States.
North Korean land mines have also previously been washed into South Korea by swollen rivers, killing or injuring civilians. In August 2015, land mine explosions seriously injured two South Korean soldiers, further raising tensions between the two Koreas.