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Kim Jong Un seen beside apparent submarine in state media photographs

(CNN) North Korean state media released images Tuesday of leader Kim Jong Un inspecting what appeared to be a submarine under construction.

North Korea's state-run Korean Central News Agency (KCNA) reported that Kim was briefed about the submarine's operational and tactical data and combat weapon systems.

Kim expressed "great satisfaction" and "stressed the need to steadily and reliably increase the national defense capability, by directing big efforts to the development of naval weapons and equipment, such as submarines," KCNA reported.

He added that the sub would be deployed to North Korea's territorial waters to the east of the country "soon."

Three photographs released by KCNA showed Kim, in a gray suit, standing besides the hulking vessel inside a nondescript warehouse.

North Korea's state-run news agency KCNA released this image of what it says is Kim Jong Un inspecting a submarine.

Analysts said the Kim regime has sought to build a viable nuclear-armed submarine to enhance its deterrence capabilities, as the vessels are hard for adversaries to track and destroy. The regime successfully test-fired a submarine-launched ballistic missile (SLBM) in 2016.

Though Pyongyang is believed to boast a fleet of about 70 submarines, experts say most of them are likely old, loud and unable to fire nuclear-armed ballsitic missiles.

The United States assessed that the photos likely show a refurbished submarine that Washington has been aware of for more than a year, according to a senior US official with direct knowledge of the assessment.

Dave Schmerler, a senior research associate at the James Martin Center for Nonproliferation Studies, said the images suggested that the sub under construction is much larger than the one used in 2016.

"If this submarine is built for carrying and launching SLBMs it is more than likely that they would test it, to ensure that it works the way they would need it to," Schmerler said.

But it's unclear exactly how far along the newly-pictured submarine is, said Melissa Hanham, the deputy director of the Open Nuclear Network.

"The submarine is still up in a warehouse, it hasn't been put into the dry docks, it doesn't appear to be finished yet," said Hanham.

Hanham said the images do not reveal the top of the submarine. "That's where the missiles go, that's what I want to see," she said.

The one photograph released that shows a large portion of the sub appears to have been intentionally cropped at the top.

Kim is seen alongside what appears to be a sub in this image released by North Korean state media Tuesday.

Hanham said it's possible Pyongyang released images of Kim visiting a secretive military operation for political reasons, or to send a message to the United States.

"What makes it seem like signaling is they're actually producing photographs, very carefully curated photographs that don't give us as much information as we would hope to glean," she said.

Kim and US President Donald Trump agreed to resume denuclearization talks between the two sides last month, but it's unclear how far things have moved since then.

Last week, North Korea's Foreign Ministry issued a strongly worded statement chastising the US and South Korea for its plans to go ahead with joint military exercises in South Korea, calling them a "rehearsal of war.

Seoul and Washington agreed to end the large-scale drills and replace them with smaller drills, often with more computer simulation, as a way to help complement diplomacy.

North Korea said Trump committed to suspending joint military exercises during his first meeting with Kim in Singapore, and hinted that it could renege on its decision to stop testing nuclear weapons and intercontinental-range ballistic missiles should the drills go ahead.

Pyongyang has made no firm commitments to stop testing shorter range or submarine launched missiles.

"Our discontinuation of the nuclear and ICBM tests and the US suspension of joint military exercises are, to all its intents and purposes, commitments made to improve bilateral relations. They are not a legal document inscribed on a paper," North Korea's Foreign Ministry said.

CNN's Stella Ko and Yoonjung Seo contributed to this report
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