North Korea is said to have recently installed buoys near the Northern Limit Line (NLL).
 
An official with South Korea's Joint Chiefs of Staffs (JCS) said Thursday that the North began installing about ten buoys around the islands of Yeonpyeong and Baengnyeong last month.
 
The installation points are said to be close to the NLL de facto maritime border.
 
The JCS official said North Korean patrol boats have been seen evicting Chinese fishing boats to south of the buoys during the current crab season.
 
South Korean military authorities believe the buoys and the North's patrol boat activities signify that the North is now, in effect, recognizing the NLL as the de facto maritime border.
 
The North had not recognized the NLL after unilaterally declaring the Korea West Sea Maritime Military Demarcation line in September 1999, which has led to clashes in the West Sea.