SEOUL, South Korea (AP) — North Korea unveiled for the first time a nuclear-powered submarine under construction, a weapons system that can pose a major security threat to South Korea and the U.S.

State media on Saturday released photos showing what it called “a nuclear-powered strategic guided missile submarine,” as it reported leader Kim Jong Un’s visits to major shipyards where warships are built.

The Korean Central News Agency, or KCNA, didn’t provide details on the submarine, but said Kim was briefed on its construction.

In this undated photo provided on March 8, 2025, by the North Korean government, North Korean leader Kim Jong Un, center, visits a shipyard to construct warships at an undisclosed place 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 language watermark on image as provided by source reads: “KCNA” which is the abbreviation for Korean Central News Agency. (Korean Central News Agency/Korea News Service via AP) (Korean Central News Agency/Korea News Service via AP)

He also said North Korea could launch the submarine in one or two years to test its capability before its actual deployment.

North Korea has an estimated 70-90 diesel-powered submarines in one of the world’s largest fleets. However, they are mostly aging ones capable of launching only torpedoes and mines, not missiles.

In 2023, North Korea said it had launched what it called its first “tactical nuclear attack submarine,” but foreign experts doubted the North’s announcement and speculated it was likely a diesel-powered submarine disclosed in 2019. Moon said there has been no confirmation that it has been deployed.

North Korea has conducted a slew of underwater-launched ballistic missile tests since 2016, but all launches were made from the same 2,000-ton-class submarine which has a single launch tube. Many experts call it a test platform, rather than an operational submarine in active service.

In recent days, North Korea has been dialing up its fiery rhetoric against the U.S. and South Korea ahead of their upcoming annual military drills set to start Monday.

During his visits to the shipyards, Kim said North Korea aims to modernize water-surface and underwater warships simultaneously. He stressed the need to make “the incomparably overwhelming warships fulfill their mission” to contain “the inveterate gunboat diplomacy of the hostile forces,” KCNA reported Saturday.