North Korean submarines were recently removed from the International Maritime Organization's public list, just one day after being added. South Korea's Joint Chiefs of Staff is investigating the circumstances surrounding this unexpected action. The JCS reported that the previously listed North Korean submarines are no longer visible on the IMO's Global Integrated Shipping Information System. According to JCS spokesperson Col. Lee Sung-jun, North Korea withdrew the registration of the submarines, and the reasons for this decision are yet to be analyzed. The JCS and the Navy are closely monitoring the situation, and they believe that the submarines were removed from the IMO list at North Korea's request. This marks the first time that North Korean submarines have been included in the IMO list, although the country had previously registered some military vessels with the organization. The sudden withdrawal of the submarines from the list has raised questions and prompted further scrutiny from South Korea's military authorities.