In a disclosure that could shift strategic calculations across East Asia and beyond, South Korea’s Defence Minister Ahn Gyu-back told parliament on October 13, that Russia had likely provided “various technologies” to North Korea to assist in the development of submarines, The Kyiv Independent reports.

The revelation lends weight to long-standing suspicions that Moscow is exchanging military know-how for munitions, manpower, or other support in its ongoing war with Ukraine.

North Korea has over recent years advanced its underwater warfare ambitions, unveiling both ballistic missile submarines and, in March this year, what it claimed was a nuclear-powered strategic guided missile submarine, The Independent adds. Meanwhile, tensions in the Russia–North Korea relationship have increasingly centred on reciprocal security commitments. In June 2024 the two states signed a strategic cooperation agreement that includes mutual support in the event of attack. The military alignment has only grown tighter: data suggests that North Korea dispatched between 11,000 and 12,000 troops to fight alongside Russian forces in late 2024, with some Western estimates placing the number at 20,000 to 30,000.

As a result, critics warn the burgeoning partnership threatens not only European security but regional stability across the Asia-Pacific. And, while South Korea’s minister flagged Russian assistance, the precise nature of the transfers remains murky. It is not yet clear whether the technologies include propulsion systems, missile integration capabilities, stealth design, or control systems. And crucially, there is no public proof to date that North Korea has managed a successful SLBM test launch The Independent added.

Seoul has called for increased vigilance and intelligence sharing among allies though. In response, the United States, Japan, and others in the region will likely intensify maritime and undersea surveillance efforts, wary of an emerging submarine threat.