The military has modified its rules of engagement to lessen the chance of armed conflict with North Korean vessels intruding past the disputed western sea border.

Military sources said Thursday the Joint Chiefs of Staff had revised naval engagement rules so as to disallow the firing of warning shots at military, commercial and fishing vessels from the North if they are deemed to have unintentionally crossed the sea border, as in cases of storms or unavoidable circumstances.

A military officer said the new regulation is aimed at preventing accidental armed clashes along the western sea border.

In June, the two Koreas agreed to use common radio frequencies and flag signalling systems to avoid clashes on the maritime border. The western sea border known as the Northern Limit Line was the scene of bloody naval skirmishes which killed dozens of sailors on both sides in 1999 and 2000.