One staff sergeant has sustained a leg injury after a South Korean land mine exploded in the southern side of the Demilitarized Zone, the Joint Chiefs of Staff said Wednesday.

The mine exploded in the DMZ in the eastern border town of Yeoncheon, Gyeonggi Province, around noon on Sunday as the staff sergeant stepped on it while on a patrol mission with fellow soldiers, the JCS said, without disclosing the identity of the wounded soldier.

He fractured his left heel, which requires two or three months of treatment, but his injuries were limited because he was wearing anti-mine boots, according to the JCS.

The soldier is expected to recover from the wound, a JCS official said on the customary condition of anonymity.

"The mine that exploded this time appears to be our military's M-14 anti-personnel mine," the official said, citing plastic debris found at the site, as well as testimonies and the impact of the explosion. "The exact reason of the explosion is under examination."

An M-14 is a South Korea-used toe popper in a plastic case, intended to disable enemy targets.

The JCS had embargoed press reports on the explosion, citing the then on-going high-level talks between South and North Korea.

Two South Korean staff sergeants were severely injured when three land mines, which the South concluded were planted by the North, exploded in the southern half of the DMZ in Paju on Aug. 4.

The explosion led to South Korea's resumption of anti-North propaganda warfare broadcasts along the border, as well as an exchange of artillery fire, between the countries last week.

Amid heightened tensions, the countries reached a breakthrough deal to end hostilities at the border Tuesday.

The DMZ is laced with more than 1 million anti-personnel and anti-tank land mines planted by South and North Korea during and after the 1950-53 Korean War.

Since the bloody explosion earlier this month, front-line troops have been ordered to wear anti-mine boots and carry mine detectors on patrol missions. (Yonhap)