According to officials, the ship retreated after South Korea’s military responded with warning shots, News.Az reports, citing Yonhap.
The 140-meter-long North Korean vessel crossed the NLL near the South Korean border island of Baengnyeong at 5:06 a.m. and remained on the southern side for an hour, according to the Joint Chiefs of Staff (JCS).
The vessel, which departed from a port in North Korea, reportedly advanced up to 5 kilometers south of the NLL.
The South Korean military, which had been monitoring the North Korean ship’s advance toward the NLL, issued warning broadcasts, but the vessel crossed the line, triggering a South Korean Navy vessel to fire around 60 warning shots and shells.
The North Korean ship subsequently veered westward and retreated from the South’s maritime control area at around 6 a.m., JSC officials said.
The 2,800-ton ROKS Cheonan frigate was conducting operations in the area at the time of the NLL breach.
A JCS official said a dozen Chinese ships were situated near the NLL at the time, adding it was looking into the possibility that the North Korean vessel crossed the maritime border to avoid the Chinese ships nearby.
The North Korean ship, named the Toksong, reportedly changed the nationality in the ship’s automatic identification system to China after crossing the NLL, in an apparent move to conceal its identity, the official said.
The ship also had a Chinese flag attached, according to the official.
No unusual movement involving the North Korean military had been detected in connection with the incident as of Friday morning, a JCS official said.
“We will firmly maintain our readiness posture and respond resolutely to any situation to safeguard the NLL,” it said.
It marked the first NLL intrusion by a North Korean vessel in three years.
In October 2022, a North Korean merchant vessel violated the NLL in the Yellow Sea before retreating northward following warning shots from a South Korean warship.
At that time, the vessel advanced up to 3.3 km south of the NLL and remained on the South Korean side for 40 minutes.
North Korea does not recognize the NLL as the inter-Korean maritime border, claiming it should be drawn farther south.
Shortly after the 2022 border crossing, the North Korean military accused the South Korean Navy of violating what it claimed was a maritime border.