North Korea has unveiled what seems to be significant advancements in its quest to develop a nuclear-powered submarine. State media published images featuring North Korean leader Kim Jong Un, accompanied by his daughter, who is speculated to be his successor, as they toured what looks like a nearly finished submarine hull.

According to the Korean Central News Agency (KCNA), North Korea’s official state broadcaster, Kim and his daughter inspected the construction of an 8,700-ton-class nuclear-propelled submarine during their visit to the shipyard. As reported by The Associated Press, Pyongyang intends to equip this submarine with nuclear armaments. Kim has emphasized that this project is pivotal for modernizing and enhancing the nuclear capabilities of North Korea’s naval forces.

The release of these images on Christmas Day is the first update provided by North Korean state media on the nuclear-powered submarine since March. Previous visuals primarily showcased the lower parts of the vessel. The KCNA, however, did not specify the exact date when these latest photos were taken.

In an undated photo released on December 25, 2025, by the North Korean government, leader Kim Jong Un is seen inspecting a nuclear-powered submarine under construction at an undisclosed location in North Korea. Independent journalists were not permitted to attend this event, and the images distributed by the North Korean government cannot be independently verified. (Korean Central News Agency/Korea News Service via AP)

Submarine expert Moon Keun-sik from Seoul’s Hanyang University commented to the AP that the images of a nearly completed hull suggest that many critical components are already installed, as submarines are typically constructed from the inside out. However, the exact extent of North Korea’s progress remains uncertain.

“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,” Moon, who also served as a submarine officer in the South Korean navy, told the AP. Moon added that North Korea’s submarine could be ready for testing at sea within months.

In this undated photo provided Thursday, Dec. 25, 2025, by the North Korean government, its leader Kim Jong Un, third left, visits a shipyard as he inspects a nuclear-powered submarine under construction at an undisclosed location in North Korea. Independent journalists were not given access to cover the event depicted in this image distributed by the North Korean government. The content of this image is as provided and cannot be independently verified. (Korean Central News Agency/Korea News Service via AP)

While at the shipyard, Kim condemned South Korea’s efforts to develop its own nuclear-powered submarine as an “offensive act,” despite the fact that President Donald Trump has backed Seoul’s push toward the technology. Kim said South Korea’s efforts violate North Korea’s security and maritime sovereignty, according to the AP.

In October, during his tour of Asia aimed at securing investments, Trump said that the U.S. would share technology with South Korea that would allow it to build a nuclear-powered submarine. The president posted on Truth Social that the vessel would be built in Philadelphia.

In this undated photo provided Thursday, Dec. 25, 2025, by the North Korean government, its leader Kim Jong Un inspects a nuclear-powered submarine under construction at an undisclosed location in North Korea. Independent journalists were not given access to cover the event depicted in this image distributed by the North Korean government. The content of this image is as provided and cannot be independently verified. (Korean Central News Agency/Korea News Service via AP)

“South Korea will be building its nuclear-powered submarine in the Philadelphia shipyards, right here in the good ol’ U.S.A. Shipbuilding in our country will soon be making a BIG COMEBACK,” the president wrote.

The White House underscored the point when it released a fact sheet in November which directly referenced Washington and Seoul’s efforts to “further our maritime and nuclear partnership.”