The Navy of the South Korea had fired warning shots after the fishing vessels belonging to North Korea had ventured beyond the disputed border of the Yellow Sea, the ministry mentioned.

Soon after all the six North Korean boats in sight had returned to their side of the border.
"Our naval patrol boats twice fired machine gun rounds at the fishing vessels. Afterwards the North Korean vessels retreated to their territory," a spokesperson for the ministry said.

In the recent weeks North Korean fishing vessels had breached the borders quite a few times.
Yonhap had mentioned that a senior military official would take action if such incursions do not cease. He said, "If North Korean boats repeatedly cross (the border) for fishing, the military will promptly and sternly respond, without hesitation”.

The Northern Limit line was unilaterally marked by the United Nations after being led by the US after the Korean War of 1950-53. This border however was not recognized by Pyongyang. Both the countries are still technically at war since the earlier was more of a truce rather than a peace treaty.

This maritime border had witnessed deadly naval clashes in 1999, 2002 and 2009.

(AW- Anil)