A North Korean patrol boat and fishing vessel violated the maritime boundary between the two Koreas early Friday morning, according to the South Korean Joint Chiefs of Staff (JCS).

The two vessels stayed in the waters south of the Northern Limit Line (NLL) – the maritime boundary between North and South Korea on the Yellow Sea – for eight minutes from 7:30 a.m., moving South about 640 meters near South Korea’s Yeonpyeong Island.

“Our military fired five warning shots with 40mm naval guns, after sending a warning broadcast. North Korean vessels returned to the northern side of the NLL at