South Korean authorities believe that the North Korean fishing boat that was seized and sent back after crossing the Northern Limit Line maritime border on March 27 deliberately entered South Korean waters.

"The fishing boat that was seized had some basic fishing equipment like a navigational compass and net, but the net was not in a state in which actual fishing was possible," a South Korean government source said on Sunday. "There were no signs of actual fishing."

"Visibility on that day was around 90 meters, meaning that conditions were generally terrible," the source said. "But the North Korean ship approached the NLL late in the afternoon and crossed the line around 5:26 p.m."

This fishing boat said it would return to the north following warnings from South Korean vessels. but did not actually do so and remained in South Korean waters and was eventually captured by the South Korean navy. 

The source also said that around ten North Korean ships were stationed north of the NLL when the fishing boat entered South Korean waters, adding that the crossing appears to have been a deliberate attempt.