South Korean officers injured in DMZ explosion, possibly caused by a landmine, according to local media reports.

Three South Korean military officers have been wounded in an explosion in the western sector of the Demilitarized Zone (DMZ) that separates North and South Korea, Seoul’s Joint Chiefs of Staff (JCS) said.

The cause of Monday’s explosion was not immediately clear, the Ministry of Defence said.

Two of the officers were evacuated from the site by helicopter, while the third was transported by land before being airlifted, according to the ministry. The officers are being treated at a military hospital near the capital Seoul, it said.

Mine explosions and other blasts are a recurring hazard in and around the DMZ, where legacy ⁠devices and suspected stray mines have periodically wounded military personnel on both sides.

The DMZ, which is 248km (154 miles) long and 4km (2.5 miles) wide, is one of the world’s most heavily armed borders. An estimated 2 million mines are peppered inside and near the border, which is also guarded by barbed wire fences, tank traps and combat troops on both sides. The zone is a legacy of the Korean War from 1950 to 1953, which ended with an armistice but not a peace treaty.

There have been growing concerns in South Korea about increased activity by North Korean soldiers near the military demarcation line as the North strengthens its border defences during prolonged tensions.