The Defense Ministry says the Northern Limit Line (NLL) has been the de facto western sea border with North Korea for 50 years, pledging to maintain that status until the two Koreas agree on a new border.

Ministry spokesman Kim Hyung-gi made the remark in a briefing Friday when asked how far the South Korean military's protection duties extended. He said they go as far as the Military Demarcation Line on land and the NLL in the sea.

The spokesman added that the two Koreas share a special temporary relationship ahead of unification, adding that the 1992 South-North Basic Agreement also states that each side will have jurisdiction over the territory it has ruled until a new maritime border can be set.