North Korean crosses de facto maritime border known as the Northern Limit Line SEOUL: A North Korean has defected to the South across the de facto maritime border known as the Northern Limit Line, according to South Korea’s Yonhap news agency. “1 N. Korean defects across maritime border in Yellow Sea: military,” the agency said in a one-line report. The resident crossed the Northern Limit Line in the Yellow Sea, a contested sea border off the west coast. South Korea’s defense ministry declined to comment when asked about the report. The number of North Korean defectors arriving in the South had hit an all-time low during the pandemic when Pyongyang moved to tightly seal its borders.