7 NK fishing boats violate S. Korean waters twice in one day . SEPTEMBER 13, 2012 08:24. . Seven North Korean fishing boats briefly crossed a tense maritime border with South Korea in the Yellow Sea Wednesday, only to return to the North after a South Korean patrol vessel broadcast a warning message.

According to South Korea’s Joint Chiefs of Staff, the seven fishing boats crossed the Northern Limit Line at around 7:30 a.m. Wednesday, advancing 0.8 mile south of the inter-Korean maritime border. After a South Korean naval patrol ship ordered them to retreat and conducted a demonstration maneuver, the fishing boats returned to their waters at around 8:30 a.m.

At around 9:21 a.m., the seven fishing boats were spotted again in the South Korean side of the border, and the South Korean patrol ship made them retreat. The situation ended when all the fishing boats returned to the North Korean side of the border around noon, the Joint Chiefs of the Staff said.

About 40 South Korean fishing boats were on the southern side of the border at the time of the operation. The South Korean Navy had all of them go to Yeonpyeong Island and put a South Korean cruise ship on stand-by until the situation ended.

“This was the second time this year that North Korean fishing boats crossed the Northern Limit Line,” a South Korean military official said, adding that a North Korean patrol boat was also spotted in the northern side of the border but that no military standoff ensued because it did not violate the de facto sea border.

“Considering the circumstances, the North Korean fishing boats presumably crossed the border while catching crabs,” the official said. “Still, we are analyzing the intention and background of the violation because it is rare that North Korean fishing boats violate the Northern Limit Line twice in one day.”

Other observers say the North did not try to stop the fishing boats from violating the border to check the South’s preparedness or seek an accidental clash.