South Korea's military said Wednesday it will upgrade thermal observation devices installed at the heavily fortified inter-Korean border to cope with growing threats from North Korea.

The upgrade aims to closely monitor and detect any provocative movements from the North along the Demilitarized Zone. In August last year, two South Korean soldiers were seriously injured after land mines planted by the North exploded.

"The Defense Agency for Technology and Quality has begun upgrading TODs which can prevent another land-mine attack," a military official said. "We are focusing on improving the device's ability to detect the movement of North Korean soldiers despite bad weather such as heavy fog."

The military said when North Korean soldiers infiltrated the southern side of the DMZ to plant the land mines last year, existing surveillance equipment failed to detect the movement.

The DMZ, which bisects the Korean Peninsula, is a 4-kilometer-wide strip of rugged no-man's land stretching from coast to coast and is a legacy of the 1950-53 Korean War that ended in a truce, not a peace treaty. South and North Korean military forces face off against each other along this demarcation line.

The DTAQ plans to complete the upgrade by the end of this year after finishing related tests, the military said. (Yonhap)