By Kang Hyun-kyung
Staff Reporter

The South Korean military is on high alert, particularly near the northern sea border off the West Sea, following Pyongyang's Friday announcement that it will scrap all political and military agreements signed with the South over the past decade.

Referring to the northern limit line (NLL), the North officially announced it is no longer considering the line a maritime borderline between the South and the North in the waters off the west of the Korean peninsula.

``Given the South government's plot to destabilize inter-Korean agreements of the past decade, articles dealing with the maritime border line are no longer valid,'' said the North in a statement, adding it agreed to recognize the NLL as a sea borderline not because it ``was set by the United States'' decades ago, but because doing so would help prevent possible military clashes and war on the peninsula.

The inter-Korean agreement of 1992 has codes on the maritime borderline. Both sides agreed at the time that they would continue to negotiate the so-called non-aggression maritime borderline until a new agreement on the sea borderline is reached.

Over the past decades, the NLL, which was set by United Nations Commander Mark Clark at the end of the Korean war in 1953, has been considered a practical sea borderline by both sides.

Despite the shared assumption, the North has crossed the line on several occasions in the past decade, leading to bloody maritime military clashes twice that took scores of lives of seamen in both sides.

North Korean patrol boats crossed the line in 1999, firing at a South Korean Navy patrol boat 14 miles away from Yeonpyeong Island, and three miles south of the NLL. The military clash took the lives of four seamen and injured 20.

Since 1999, shortly after the first West Sea battle took place, the North repeatedly claimed the sea border was further south.

North Korean naval vessels crossed the line again in 2002, exchanging fire with South Korean patrol boats.

After the second West Sea battle, the North committed to accept the NLL as the maritime borderline during inter-Korean defense ministry talks held in November 2007.

Given the two military clashes in the West Sea, defense experts say they cannot rule out the possibility of a third one in the area.

hkang@koreatimes.co.kr