Three South Korean military officers were injured on Monday in a suspected landmine explosion inside the Demilitarised Zone separating North and South Korea, according to Seoul’s military.

The explosion occurred at about 10:50am south of the Military Demarcation Line in the western sector of the DMZ while personnel were conducting an operation to clear a route and search for mines and other explosives, South Korea’s Joint Chiefs of Staff said.

Two senior officers suffered serious injuries, including one who lost an ankle, according to military sources cited by Yonhap. None of the three officers was reported to be in life threatening condition.

An emergency helicopter was sent into the heavily fortified border zone in coordination with the United Nations Command to evacuate the injured personnel.

Cause of explosion under investigation

South Korean military authorities said the cause had not yet been conclusively established, although officials said there was a high probability that a landmine caused the blast.

It also remained unclear whether any mine involved had originally been placed by North Korea or South Korea. Investigators are considering several possibilities, including that a mine was disturbed during the route clearing operation or that a North Korean mine had been displaced by recent heavy rainfall.

The blast occurred in an area controlled by the South Korean Army’s 25th Infantry Division. A South Korean opposition lawmaker suggested the site was close to an area where North Korean troops were suspected of crossing the military boundary to plant mines, but the Joint Chiefs of Staff disputed that characterisation, saying the locations were some distance apart.

South Korea has previously said it detected terrain changes south of parts of the military boundary and was consulting the United Nations Command over the possibility that North Korean forces had planted mines there.

One of the world’s most heavily fortified borders

The DMZ has divided the Korean Peninsula since an armistice ended major fighting in the Korean War in 1953. Despite its name, the roughly 248 kilometre long buffer zone is one of the world’s most heavily militarised borders and contains large numbers of landmines.

North Korean leader Kim Jong Un declared relations between the two Koreas to be those of two hostile states in late 2023. Since April 2024, North Korean forces have reinforced the border by installing additional barbed wire, laying mines and constructing anti tank barriers along the Military Demarcation Line.

Monday’s incident was the first landmine explosion on the South Korean side of the DMZ to cause a serious injury since August 2015, when three wooden box mines planted by North Korea exploded during a South Korean patrol. One soldier lost both legs and another lost an ankle in that incident.

A separate incident occurred inside the DMZ in November 2025, when a South Korean soldier suffered an ankle fracture during a mission to detect landmines.

The latest explosion comes amid renewed tensions on the Korean Peninsula. A day earlier, North Korea fired two short range ballistic missiles from the Wonsan area towards waters off its eastern coast, with the launches taking place less than three hours apart.