North Korea has announced for the first time that it has a nuclear-powered submarine — designed to carry nuclear weapons — under construction.
If the report from state media is accurate, the news is an escalation in the development of Pyongyang’s nuclear weapons program — one that could pose a threat to the Korean Peninsula and beyond.
Photos released in March 2025 by the Korean Central News Agency (KCNA) showed a “nuclear-powered strategic guided missile submarine” in a report on North Korean dictator Kim Jong Un’s visits to a military shipyard, according to The Associated Press (AP).
The Center for Strategic and International Studies (CSIS), a Washington, D.C. think tank, said the news wasn’t a surprise given that Kim has stated his desire to acquire a nuclear-powered submarine as far back as 2021. In 2023, North Korea said it launched a “tactical nuclear attack submarine,” but experts cast doubts on the claim, saying that it was a previously disclosed diesel-powered vessel, according to AP.
National Security Council spokesperson Brian Hughes said the United States is aware of the most recent news and remains committed to the “complete denuclearization of North Korea.”
The KCNA photos show a vessel that could carry as many as 10 missiles, said Moon Keun-sik, a South Korean submarine expert at Seoul’s Hanyang University, according to AP. The use of the term “strategic guided missiles” meant it is designed to carry nuclear-capable weapons, Moon told AP. “It would be absolutely threatening to [South Korea] and the U.S.,” he said.
Still, other experts said that North Korea faces daunting challenges in this latest manifestation of Kim’s nuclear ambitions — even if it has outside help.
“North Korea does not have the capacity to produce a nuclear submarine,” Sam Tangredi, the director of the Institute for Future Warfare Studies, told Voice of America (VOA) in March 2025, according to Korea Joongang Daily, a South Korean newspaper. “That requires a substantial supply chain and infrastructure to acquire the materials and knowledge of nuclear propulsion.”
Even countries with established nuclear power programs struggle to design reactors for submarines, experts said. “The key question for North Korea in this case is that a submarine’s nuclear reactor is a very advanced technology,” Bruce Bennett, a senior researcher at the RAND Corporation, told VOA, according to Korea Joongang Daily. “I don’t think they’re going to be able to put together a submarine’s nuclear reactor without substantial Russian help.”
The CSIS report also noted that Moscow is likely providing the advanced reactor technology, noting its increasing transactional relationship with Pyongyang since Russia’s invasion of Ukraine in 2022. “North Korea has supplied munitions and troops to Russia in exchange for food, oil, cash, and commercial benefits,” the report said.
CSIS also noted another troubling ramification of a technology transfer from Moscow to Pyongyang. “[It] reflects the changing balance of influence between Russia and China over its communist neighbor,” the report said. “China has been unable to stop North Korea’s arms supply and troop deployment to Russia, which suggests that Beijing has lost its control over its neighbor.”