United States Under Secretary of Defense for Policy Elbridge Colby and South Korean Defense Minister Ahn Gyu-back agreed during talks in January 2026 to deepen cooperation on Seoul’s pursuit of a nuclear-powered submarine, South Korea’s defense ministry said. Colby visited Seoul on his first overseas trip in the post, which comes as Washington signals it expects South Korea to take a more leading role in deterring North Korea.
In a statement, the ministry said both sides viewed cooperation on a nuclear-powered submarine as a step that would strengthen South Korea’s ability to lead the defense of the peninsula and elevate the security alliance. The Pentagon’s new National Defense Strategy released in January said that it expects a “more limited” U.S. role in deterring North Korea, with South Korea taking the primary responsibility.
Ahn pressed for faster progress on the transfer of wartime operational control to Seoul and called for closer coordination on alliance follow-up measures, the ministry said. Colby, the Pentagon’s top defense and foreign policy official, said in a post on X on his arrival that South Korea is a “model ally” committed to increasing defense spending in line with U.S. regional strategy.
South Korea hosts about 28,500 U.S. troops and last year pledged to lift defense spending to 3.5% of GDP, a move that Colby and other U.S. officials have praised as strengthening Seoul’s role in deterring North Korea. Colby also visited Japan during his Asian trip.