Overview

• Intelligence cited by South Korea suggests Russia supplied North Korea with two to three nuclear submarine modules, including a reactor, turbine and cooling system.
• The components were reportedly taken from decommissioned Russian submarines and delivered in the first half of this year.
• South Korean authorities are assessing the credibility of the information and have briefed the United States and partner governments without issuing confirmation.
• Experts say Pyongyang has lacked the know-how to build a submarine reactor and could use any acquired unit for on‑land testing and reverse‑engineering.
• A confirmed transfer would raise serious nonproliferation concerns under the NPT and could prompt additional sanctions on Russia and North Korea.