A North Korean merchant ship violated the Northern Limit Line (NLL) in the Yellow Sea at about 5:06 a.m. on the 26th but retreated after warning shots by South Korea's military. It was the first NLL intrusion by a North Korean vessel in about 2 years and 11 months since Oct. 24, 2022. Authorities also detected signs that the ship tried to pass itself off as Chinese, including by flying the Five-Star Red Flag.
The Joint Chiefs of Staff said, "At about 5 a.m. today in waters northwest of Baengnyeong Island, the North Korean merchant ship Duksung-ho violated the NLL about 50 kilometers northwest of Baengnyeong Island in the Yellow Sea, prompting our military to issue warning broadcasts and fire warning shots," adding, "The North Korean merchant ship then exited our jurisdictional waters." The merchant ship is known to have intruded as far as 5 kilometers south of the NLL for about an hour.
The military authorities had been closely monitoring Duksung-ho's movements as it approached the NLL, and when it crossed the NLL despite repeated warning communications, the Daegu-class frigate Cheonan (2,800 tons), which was on a security operation, conducted about seven rounds of warning fire with machine guns and naval guns, totaling around 60 shots. Duksung-ho then turned west and withdrew at about 6 a.m.
There were also indications that Duksung-ho tried to disguise itself as a Chinese-flagged vessel after the NLL intrusion. A Joint Chiefs official said, "After violating the NLL, Duksung-ho arbitrarily changed its nationality in the Automatic Identification System (AIS) from North Korean to Chinese. When our ship approached after the NLL violation, Duksung-ho was flying the Five-Star Red Flag," adding, "It changed its nameplate in the middle—an attempt to conceal its nationality."
It is unclear why Duksung-ho acted this way. However, because the waters are the high seas, and Chinese vessels—unlike North Korean vessels—can pass freely, some analysts suggested it may have tried to disguise its nationality.
No unusual North Korean military activity was identified in connection with the incident. It is also being tentatively assessed that the likelihood Duksung-ho intentionally violated the NLL is low.
A Joint Chiefs official said, "About a dozen Chinese fishing boats were near the NLL at the time," adding, "We are analyzing the possibility that it crossed the NLL while changing course to avoid the Chinese fishing boats." The official continued, "Our military responded in accordance with operational procedures while closely monitoring North Korean movements," adding, "With readiness firmly established, we will resolutely respond to any situation and defend the NLL."