SEOUL, South Korea (AP) — The South Korean and U. “At a time when its efforts to build (bigger submarines) have reported little progress due to the sanctions, North Korea wants to show it’s still almost developed the types of missiles that can be fired from a submarine,” said Moon Keun-sik, a submarine expert who teaches at Kyonggi University in South Korea. ” It said North Korea will take “the toughest counteraction against the most vicious hostile plots of the U