North Korea’s newly unveiled nuclear-powered submarine, reportedly made with Russian technology, could pose a major security challenge to neighbour South Korea and its ally the US, experts said.
The Korean Central News Agency on Saturday released photos of what it called an under-construction “nuclear-powered strategic guided missile submarine”, ticking off a key item on a wishlist of sophisticated weaponry that leader Kim Jong Un had vowed, at a major political conference in 2021, to introduce to tackle US-led “military threats”.
Inspecting the submarine, Mr Kim warned that North Korea would never tolerate “maritime and underwater military activities of the hostile forces, which seriously threaten the country’s sovereignty and interests through the constant deployment of strategic assets”.
“Overwhelmingly powerful warships must serve as a strong nuclear deterrent against hostile forces’ habitual gunboat diplomacy,” he was quoted as saying by state media Rodong Sinmun.
Pictures of the submarine were tactically released two days before South Korea and the US kicked off their annual “Freedom Shield 2025” military drills.
The vessel was likely docked at the Chongjin Shipyard, NK News reported.
Features of the submarine
Photos of the submarine released by Pyongyang showed only the lower hull of the vessel and 15 rail-based cradle stands. It appeared to be a 6,000-tonne or 7,000-tonne vessel, which could carry around 10 missiles, Moon Keun Sik, a South Korean submarine expert at Seoul’s Hanyang University, said.
He pointed out that the use of the phrase “strategic guided missiles” meant the vessel could carry nuclear-capable weapons.
The submarine appeared at least 117m long, twice the size of Hero Kim Kun Ok, the North’s first ballistic missile submarine revealed in 2023.
Pyongyang already has an estimated 70-90 diesel-powered submarines, giving it one of the world’s largest fleets. However, they are mostly aging vessels capable of launching only torpedoes and mines, not missiles.
North Korea has conducted a slew of underwater-launched ballistic missile tests since 2016, all from the same 2,000-tonne submarine with a single launch tube. This particular submarine has been described by experts as a test platform rather than an operational submarine in active service.
Likely use of Russian technology
The unveiling of the vessel raised questions about how North Korea, a heavily sanctioned country, could marshal technology and resources to construct nuclear-powered submarines.
Analysts said Pyongyang could have received Russian technological help to build a nuclear reactor for the submarine in return for sending conventional weapons and, allegedly, soldiers to aid Moscow’s war effort in Ukraine.
South Korea’s spy agency previously claimed that 12,000 North Korean troops were fighting in the Russian border province of Kursk to repel a Ukrainian invasion.
Given the shape and size of the vessel, it could be a ballistic missile submarine, said Yang Uk, a defence expert at the Asan Institute for Policy Studies.
He told the Korea Times that the photos suggested the submarine had been under construction for more than two years. North Korea could have received technology from Russia in the latter half of 2023, he added.
When could the submarine be deployed?
It could take “at least four to five more years to deploy the submarine into the Pacific Ocean” as the vessel needed to go through more procedures, including testing, experts said.
But if Pyongyang indeed got Russian assistance to develop a compact nuclear reactor capable of withstanding deep-sea pressure, the vessel could be deployed faster.
North Korea could aim to deploy naval vessels in international waters beyond the 12-nautical-mile limit of its territorial sea.
What are North Korea’s rivals saying?
Pyongyang has dialled up its fiery rhetoric against the US and South Korea ahead of their annual military drills, which involve responding to evolving challenges like the North’s growing partnership with Russia.
Pyongyang obtaining a greater ability to fire missiles from underwater is a worrying development because it is difficult for its rivals to detect such launches in advance.
Mr Kim, during his recent visits to shipyards, said North Korea aimed to modernise water-surface and underwater warships simultaneously. He stressed the need to make “the incomparably overwhelming warships fulfil their mission” to contain “the inveterate gunboat diplomacy of the hostile forces”.
South Korea’s ministry of unification said it was monitoring any signs of Russian transfer of technologies to the North. “The transfer of military technology to North Korea is prohibited under UN Security Council resolutions. Russia, as a permanent member of the UN Security Council, must abide by UN sanctions on North Korea,” ministry spokesperson Koo Byung Sam said.
“We’re aware of these claims and do not have additional information to provide at this time,” US National Security Council spokesperson Brian Hughes said. “The US is committed to the complete denuclearisation of North Korea.”
