North Korea Tests Submarine Missiles, Signals Possible Nuclear Deployment

North Korea has reported testing two types of submarine-launched strategic cruise missiles for the first time in nearly three years, with photographs suggesting the exercises may have involved a submarine designed to carry nuclear weapons.

North Korea conducted the tests in its eastern waters on Wednesday, with state media announcing the results a day later. The Associated Press reported that the launches came amid a series of weapons demonstrations by Pyongyang as it seeks to strengthen its nuclear deterrent and gain leverage in potential negotiations with the United States.

The Korean Central News Agency (KCNA) said the exercises were intended to assess the readiness of North Korea’s underwater combat systems and demonstrate the reliability of its nuclear deterrent. It did not identify the launch platform, but photographs released by the agency appeared to show the Hero Kim Kun Ok, a submarine unveiled by North Korea in September 2023.

If the submarine was involved, Wednesday’s launches would be its first publicly reported weapons tests. Analysts believe the tests could indicate that Pyongyang has begun evaluating weapons intended for the vessel ahead of its deployment, although its operational readiness remains uncertain.

Submarine’s Readiness Remains Uncertain

North Korea has spent years developing missiles that can be launched from underwater, a capability that could make it harder for South Korea and the United States to detect an attack before a missile is fired.

Until Wednesday’s tests, North Korea’s underwater launches had been conducted from a submarine weighing around 2,000 tonnes and equipped with a single launch tube. Many experts regard that vessel as a test platform rather than an operational submarine in active service.

The Hero Kim Kun Ok, unveiled in September 2023, was presented by Pyongyang as a submarine capable of launching tactical nuclear weapons from underwater. Images published by North Korean state media showed at least 10 missile launch tubes, in addition to its torpedo tubes.

Foreign experts, however, questioned whether the submarine could perform as North Korea claimed. Some assessed that it was likely a modification of an existing, ageing diesel-powered submarine.

According to the Associated Press, the absence of publicly known weapons tests involving the submarine over the previous three years raised questions about its technical readiness, including its ability to right itself. Shin Jong-woo, an analyst at South Korea’s Defense and Security Forum, said the latest tests indicated that North Korea had resolved those problems and begun testing weapons intended for the vessel. Shin added that North Korea would probably test ballistic missiles from the submarine before the navy deploys it.

South Korea’s Joint Chiefs of Staff said it detected the launches and assessed that the missiles had been fired from a submarine. One was launched through a vertical launch tube and the other through a torpedo tube, according to the South Korean military.

Moon Keun-sik, a submarine expert who teaches at Seoul’s Hanyang University, said deployment of the Hero Kim Kun Ok could increase the threat to South Korea and the United States.

Its underwater-launched missiles are “formidable weapons that we don’t know when and where they would be fired,” Moon said.

Kim Jong Un Expands Focus On Naval Weapons

North Korean leader Kim Jong Un has recently placed greater emphasis on strengthening the navy after a decade of expanding the country’s ballistic missile programme.

In March 2025, North Korea unveiled its first nuclear-powered submarine, which was still under construction. The completion date remains unclear.

The launches followed tests of several hypersonic missile systems on September 20 and October 3, which North Korea said were intended to advance weapons designed to overwhelm missile defence systems in South Korea and Japan.

The latest launches also followed renewed tensions over attempts to restart diplomatic engagement between Washington and Pyongyang.

In August, North Korea rejected what it viewed as an effort by US President Donald Trump to revive talks by scaling back a joint military exercise with South Korea. Pyongyang said shortening the duration of the drill would not change its hostile nature.

North Korea has previously indicated that it could return to negotiations if Washington abandoned its “hostile” policy towards Pyongyang and dropped denuclearisation as a precondition for talks.

Missile Tests Reinforce North Korea’s Nuclear Position

Moon said the latest launches were intended to strengthen Pyongyang’s leverage in potential negotiations with Washington. He interpreted the tests as an attempt to demonstrate that North Korea would retain its nuclear arsenal and expand its nuclear capabilities at sea.

“North Korea would want to say it would never give up its nukes,” Moon said.

“It’s sending a message to the US saying that ‘We’ve perfected land-abased nuclear weapons and are deploying nuclear weapons to the maritime domain so that you shouldn’t demand our denuclearization any longer.’”

If the Hero Kim Kun Ok was involved, the launches would mark its first publicly reported weapons tests. Its readiness for operational deployment remains uncertain.