A North Korea patrol ship was forced back into Northern waters Tuesday after receiving warning shots from the South Korean Navy after the ship crossed the inter-Korean sea border, the Joint Chiefs of Staff said.
  

The patrol ship came down about 1.5 kilometers south of the Northern Limit Line at 10:22 a.m., the JCS said in a press release, adding that the Navy fired warning shots, along with a warning message before the North Korean ship retreated. 
  

North Korea often trespasses the de facto maritime border, challenging the legitimacy of the NLL drawn by the U.S.-led United Nations Command after the 1950-53 Korean War.
  

It is the eighth time the North has violated the NLL so far this year.
  

"The South Korean military stands with full combat readiness, with a close eye kept on the movement of the North Korean military," the statement said. (Yonhap)