SEOUL, Nov. 13 (Xinhua) -- South Korea on Friday calmly responded to the Democratic People's Republic of Korea (DPRK)'s latest warning on disputed waters, describing it as only "rhetoric".

    The DPRK said earlier in the day it will take "merciless military measures" to defend its own sea demarcation line in the West Sea, and South Korea will pay the cost for a recent naval clash.

    The DPRK has repeated similar threats since the beginning of this year, so Seoul preliminarily regarded it as a "rhetoric", the Defense Ministry told Xinhua.

    The ministry also noted that there were no particular situation detected in waters of the area.

    However, the ministry said the military has stepped up readiness to response any provocation by the DPRK side.

    South Korea and the DPRK's naval boats exchanged fire off west coast of the Korean Peninsula near the Northern Limit Line (NLL) area Tuesday morning, but no casualties were reported. The two sides blamed each other for the clash.

    The NLL was fixed unilaterally by the U.S.-led United Nations Command after the Korean War (1950-1953). Seoul holds the NLL as the de-facto western inter-Korean maritime border, but Pyongyang does not accepted it, and declared its maritime military control zone off west coast of the Korean Peninsula in September 1999.