The military says North Korean patrol boats have crossed the Northern Limit Line (NLL) into South Korean territorial waters 23 times this year, while North Korean fishing vessels have intruded in the waters 25 times.

The figure for patrol boats is three times bigger compared to last year and two-point-six times bigger for fishing boats.

An official at the South Korean Joint Chiefs of Staff said Thursday that, for the most part, North Korean fishing vessels trespassed over the NLL maritime border during the crab catching season. North Korean patrol boats, meanwhile, were found to have crossed the NLL in the process of cracking down on the activities of such fishing boats.

The South Korean military was estimated to have issued warning messages and implemented measures to counter the intrusions 47 times this year to seek the North Korean boats' retreat to the communist state.