SEOUL, Aug. 26 (UPI) -- The disappearance of 50 North Korean submarines from South Korean military detection is a source of concern for U.S. and South Korea forces as the recent military buildup sheds new light on Pyongyang's naval tactics.
South Korea military officials said Tuesday that 70 percent, or 50 of the 77 submarines North Korea deployed from bases on Aug. 21 were no longer appearing on South Korean sonar, but it is likely they had returned to naval bases in North Korea, South Korean news agency Yonhap reported.
But on Wednesday South Korean Defense Ministry spokesman Kim Min-seok did not provide a clear confirmation of North Korean submarine movements, according to South Korean television network SBS.
"We've said before the disappearance [of North Korean submarines] is a source of concern, and the fact is they are not easy to detect when they are submerged under water," Kim said.
Seoul's military said the latest North Korea buildup provided new insight into how Pyongyang would launch an attack on South Korean territory. Submarines would be used to deploy Special Operations personnel to lay mines in South Korean port cities like Busan and Ulsan in order detonate nuclear power plants and other facilities.
"[North Korea's] deployment of a large fleet of submarines could be seen as a way of creating a distraction when launching a simultaneous attack against major ports and facilities in South Korea," said Moon Geun-sik, a former South Korean Navy captain.
On Wednesday in the South Korean coastal country of Uljin, police were placed on high alert when they received a call about a suspicious object that looked like a submarine about nine miles from the coast, South Korean outlet Newsis reported.
The call prompted the Navy to dispatch Lynx anti-submarine helicopters and other maritime patrol aircraft but the vessel at sea was later identified as a Russian cargo ship.