North Korea on Thursday released new state media images that suggest major progress on a nuclear-powered submarine program, a development that could significantly reshape security dynamics on the Korean Peninsula. 

The photos, published by the Korean Central News Agency (KCNA), show leader Kim Jong Un inspecting what appears to be a nearly finished submarine hull during a visit to a shipyard. 

The disclosure came as Kim sharply criticized South Korea’s own plans to pursue nuclear-powered submarines, calling them a direct threat to the North.

Images point to advanced construction stage

KCNA said the leader inspected the construction of what North Korea describes as an 8,700-ton-class nuclear-propelled submarine. The vessel has previously been described by the regime as a “strategic guided missile submarine” or a “strategic nuclear attack submarine,” indicating it is intended to carry nuclear weapons. 

The project has been framed as a central part of his effort to modernize and nuclear-armed the country’s navy.

The agency did not say when the inspection took place, but the released images show the leader walking alongside a massive burgundy-colored vessel inside an assembly hall. The hull appears to be coated with anti-corrosion paint and largely complete. Senior officials accompanied him, along with his daughter. 

This marks the first time since March that North Korean media has released images of the submarine, and earlier photos only showed partial lower sections of the hull.

The nuclear-powered submarine is claimed to be 8,700 ton. Image credit: KCNA

Experts assess launch timeline and capabilities

It remains unclear how close the submarine is to operational readiness. Still, experts say the images suggest substantial progress. Submarines are typically built from the inside outward, meaning that a completed hull often indicates that major internal systems are already installed.

“Showing the entire vessel now seems to indicate that most of the equipment has already been installed, and it is just about ready to be launched into the water,” said Moon Keun-sik, a submarine expert at Seoul’s Hanyang University. 

He further added that the vessel could possibly be tested at sea within months.

A nuclear-powered submarine would give North Korea greater ability to launch missiles from underwater, a capability that is difficult to detect in advance. That makes it a serious concern for regional security planners, even as doubts remain over whether the heavily sanctioned country can fully support such a complex system.

North Korean leader Kim Jong Un received a briefing on the country’s first nuclear-powered submarine. Image credit: KCNA

Kim links project to regional rivalry

During the shipyard visit, the North Korean leader condemned South Korea’s pursuit of nuclear-powered submarine technology, an effort backed by U.S. President Donald Trump. He described the South’s push as an “offensive act” that severely violates North Korea’s security and maritime sovereignty.

He argued that Seoul’s plans only reinforce the need for Pyongyang to strengthen its own naval forces. He claimed the completion of the submarine would be an “epoch-making” step in boosting the country’s nuclear war deterrent against what he called enemy threats.

A nuclear-powered submarine was first listed in 2021 as part of a broader weapons development plan. That list also included solid-fueled intercontinental ballistic missiles, hypersonic weapons, reconnaissance satellites, and multi-warhead missiles. Since then, North Korea has carried out a series of tests aimed at advancing those systems.

Russia ties and rising peninsula tensions

Questions persist about how North Korea is sourcing the technology and materials needed for a nuclear-powered submarine. Some analysts point to Pyongyang’s growing alignment with Russia, including its reported support for President Vladimir Putin’s war in Ukraine, as a possible pathway for technical assistance.

While there has been speculation that North Korea could obtain a reactor from Russia, possibly from a retired submarine, Moon said it is more likely the country designed its own reactor, though some outside help may have been involved.

Separately, KCNA reported that Kim on Wednesday supervised a test of a new long-range anti-air missile fired toward the eastern sea. South Korea’s Defense Ministry did not immediately comment.

These developments come as tensions on the Korean Peninsula continue to rise. North Korea has rejected renewed calls from Washington and Seoul to resume talks aimed at reducing its nuclear and missile programs, which stalled after a failed summit with Trump in 2019.