The US-led United Nations Command has said it is inspecting warning markers set up near the Demilitarized Zone (DMZ) to alert pilots they are approaching North Korea's airspace so as to prevent accidental border crossings.

Currently, dozens of red-colored panels, named Aircraft Warning Panel Markers (AWPM), are set up near the southern limit line of the buffer zone to give such warnings to pilots. Those are about a minute's flight from the Military Demarcation Line.

"This week, UNC personnel are flying the length of the DMZ's southern boundary to verify that the markers are still intact and visible. If not, we'll work to clear the foliage and replace the markers, since AWPMs help ensure that both civilian and military aircraft avoid flying into the DPRK by mistake," the command said in its Facebook post Wednesday.

The DPRK stands for North Korea's official name, the Democratic People's Republic of Korea.

The maintenance mission comes as a civilian aircraft accidentally crossed the border into North Korea in April last year after entering the airspace above the DMZ near the county of Hwacheon, Gangwon Province, according to the UNC.

An investigation into the incident found that the civilian pilot was unable to observe the marks along the southern boundary, and this week's mission is a follow-up measure, it added.

"Mitigating incidents is one of many ways we support peace on the Korean Peninsula," the command said. UNC administers the buffer zone and enforces the Armistice Agreement that halted the 1950-53 Korean War.

In January 2005, the UH-60 Blackhawk of the US Forces Korea flew past the non-flight line near the DMZ during routine training, and narrowly avoided crossing the border into the North after South Korean troops fired a flare gun shot. (Yonhap)