A North Korean patrol boat has violated the Northern Limit Line (NLL), the de facto border in the Yellow Sea, and retreated after receiving warning shots from the South Korean Navy.

The Joint Chiefs of Staff (JCS) said that the patrol ship crossed about one-point-two kilometers past the NLL at 10:22 a.m. on Tuesday.

The South Korean Navy is reported to have fired warning shots along with a warning message, forcing the North Korean ship back.

The JCS said that the South Korean military is stepping up its surveillance on the North Korean military.