SEOUL, July 3 (Yonhap) -- The government on Wednesday rejected all suspicions of a cover-up in connection with last month's undetected arrival of a North Korean boat at an east coast port, even though it acknowledged a "grave mistake" in securing the border and reprimanded top military commanders.
The government has been under fire following revelations that the military failed to detect the small wooden boat carrying four North Koreans until it traveled all the way to the port of Samcheok, about 130 kilometers away from the eastern sea border, and a civilian alerted police about it on June 15.
Fueling the criticism were allegations that the military gave an incorrect account of what happened, including saying the boat was found in the "vicinity" of the port, not at the port, sparking widespread suspicions that it tried to cover up the border security failure.
"The investigation into the case found a failure in the military's surveillance operations and a failure in appropriately informing the public of the case," Defense Minister Jeong Kyeong-doo said during a news conference to announce the results of a weekslong investigation into the case.
Calling the security lapse an "unacceptably grave mistake," the ministry relieved the commander of the Army's 8th Corps of his duty, holding him responsible for the failure in his operational area.
The government also rebuked Joint Chiefs of Staff (JCS) Chairman Park Han-ki, and referred Maj. Gen. Lee Gye-cheol, who leads the Army's 23rd Infantry Division, and R. Adm. Kim Myeong-soo, commander of the Navy's First Fleet, to the military's disciplinary committee.
The Army is in charge of coastal operations, and the Navy conducts missions for maritime defense.
According to the government probe, the 1.8-ton wooden boat with a 28-horsepower engine left the North's Hamgyong Province on June 8 and crossed the Northern Limit Line (NLL) unchecked about four days later on June 12.
After moving further south the following two days, the men turned the engine off late on June 14 and stayed overnight at sea until dawn. The boat then began moving to the port and reached the dock at around 6:20 a.m. on June 15.