North Korea’s leader Kim Jong-un has been photographed inspecting a newly-built submarine, potentially signalling continued development of a submarine-launched ballistic missile (SLBM) programme.

Mr Kim was seen looking over the weapon systems of the vessel built under “his special attention” in photos released on Tuesday by the state news agency KCNA.

The organisation said the submarine would soon be deployed in the waters off North Korea’s east coast, without providing any details on the weapon systems. Analysts claimed the size of the watercraft indicated it was designed to carry missiles.

“We can clearly see that it is a massive submarine – much larger than the existing one that’s been well known since 2014,” said Ankit Panda, senior fellow at the US-based Federation of American Scientists.

“What I find significant about the political messaging here is that this is the first time since a February 2018 military parade that he has inspected a military system clearly designed to carry and deliver nuclear weapons.”

North Korea: A road trip on the edge of the Chinese border Show all 20 1 /20 North Korea: A road trip on the edge of the Chinese border North Korea: A road trip on the edge of the Chinese border People have their picture taken with North Korea in the background, in Tumen, China. In the Chinese city of Dandong, signs of neighbouring North Korea are pervasive. REUTERS North Korea: A road trip on the edge of the Chinese border A North Korean woman is photographed from the Chinese side of the Yalu River near the town of Changbai, China as she walks between houses in the North Korean town of Hyesan. A week-long road trip along China's side of its border with North Korea revealed stark contrasts between China's bright towns and North Korea's dark villages. REUTERS North Korea: A road trip on the edge of the Chinese border North Korean souvenirs are displayed for sale on the banks of the Yalu River in Dandong in Liaoning province, China. In the Chinese city of Dandong, signs of neighbouring North Korea are pervasive. Reuters North Korea: A road trip on the edge of the Chinese border A large screen, which faces North Korea, broadcasts propaganda videos on an island on the Yalu River between North Korea and China, in the town of Linjiang in Jilin province, China. A week-long road trip along China's side of its border with North Korea revealed stark contrasts between China's bright towns and North Korea's dark villages. REUTERS North Korea: A road trip on the edge of the Chinese border A piece of clothing is used to make a gap in barbed wire near the closed bridge over the Yalu River on the Chinese side of the border with North Korea between towns of Ji'an and Linjiang, China. A week-long road trip along China's side of its border with North Korea showed places where it is porous. Reuters North Korea: A road trip on the edge of the Chinese border A tourist uses binoculars to look across to North Korea from a tower built on the Chinese side of the border between Russia (L), China (C) and North Korea (R) near the town of Hunchun in China. Reuters North Korea: A road trip on the edge of the Chinese border North Koreans are photographed from the Chinese side of the border as they stand next to the freezing Yalu River near the town of Linjiang, China. On a road trip along China's side of its border with North Korea, reporters found a group of North Koreans diving in the Yalu river who the Chinese locals said were searching for gold. REUTERS North Korea: A road trip on the edge of the Chinese border Women participate in a group dance exercise close to the Yalu River which runs between China and North Korea, in the town of Linjiang in Jilin province, China. A week-long road trip along China's side of its border with North Korea revealed stark contrasts between China's bright towns and North Korea's dark villages. REUTERS North Korea: A road trip on the edge of the Chinese border A sign reading, "Take the initiative to preserve order along the border," stands in a field at the border between China and North Korea just outside Dandong, Liaoning province, China. Reuters North Korea: A road trip on the edge of the Chinese border A couple prepare for a wedding photography session on a boat which takes tourists on sightseeing tours from the Chinese side of the Yalu River, close to the shores of North Korea, near Dandong, Liaoning province, China. In the Chinese city of Dandong, signs of neighbouring North Korea are pervasive. REUTERS North Korea: A road trip on the edge of the Chinese border Tourists travel on a boat taking them from the Chinese side of the Yalu River for sightseeing close to the shores of North Korea, near Dandong, Liaoning province, China. In the Chinese city of Dandong, signs of neighbouring North Korea are pervasive. REUTERS North Korea: A road trip on the edge of the Chinese border North Koreans are photographed from the Chinese side of the border as they stand next to the freezing Yalu River near the town of Linjiang, China. On a road trip along China's side of its border with North Korea, reporters found a group of North Koreans diving in the Yalu river who the Chinese locals said were searching for gold. REUTERS North Korea: A road trip on the edge of the Chinese border Women walk across a bridge from an island on the Yalu River, dividing North Korea and China, in the town of Linjiang in Jilin province, China. A week-long road trip along China's side of its border with North Korea revealed stark contrasts between China's bright towns and North Korea's dark villages. REUTERS North Korea: A road trip on the edge of the Chinese border A North Korean soldier and locals are photographed from the Chinese side of the border north of Dandong, China as they stand on the banks of the Yalu River, north of Sinuiju, North Korea. A week-long road trip along China's side of its border with North Korea revealed stark contrasts between China's bright towns and North Korea's dark villages. REUTERS North Korea: A road trip on the edge of the Chinese border North Korean girls are photographed from the Chinese side of the border as they collect water from the frozen Yalu River near Linjiang, China. A week-long road trip along China's side of its border with North Korea revealed stark contrasts between China's bright towns and North Korea's dark villages. REUTERS North Korea: A road trip on the edge of the Chinese border A man looks through binoculars towards North Korea on the Broken Bridge over the Yalu River that connects the North Korean town of Sinuiju and Dandong in Liaoning Province, China. In the Chinese city of Dandong, signs of neighbouring North Korea are pervasive. REUTERS North Korea: A road trip on the edge of the Chinese border North Koreans are photographed from the Chinese side of the border as they stand next to the freezing Yalu River near the town of Linjiang, China. On a road trip along China's side of its border with North Korea, reporters found a group of North Koreans diving in the Yalu river who the Chinese locals said were searching for gold. REUTERS North Korea: A road trip on the edge of the Chinese border North Korean fishermen are seen as a Chinese flag flutters from the Broken Bridge as the sun sets over the Yalu River between the North Korean town of Sinuiju and Dandong in Liaoning Province, China. In the Chinese city of Dandong, signs of neighbouring North Korea are pervasive. REUTERS North Korea: A road trip on the edge of the Chinese border North Koreans are photographed from the Chinese side of the border as they stand in the freezing Yalu River near the town of Linjiang, China. On a road trip along China's side of its border with North Korea, reporters found a group of North Koreans diving in the Yalu river who the Chinese locals said were searching for gold. REUTERS North Korea: A road trip on the edge of the Chinese border Women, photographed from the Chinese side of the border, are seen through binoculars fixed on a building on the Chinese side of the border for sightseers to look across to North Korea, as they cross the bridge from Namyang in North Korea towards the town of Tumen in China, Reuters

Mr Panda added: “I take that as an ominous signal that we should be taking Kim Jong-un’s end-of-year deadline for the implementation of a change in US policy with the utmost seriousness.”

North Korea has a large submarine fleet, but only one known experimental submarine capable of carrying a ballistic missile.

A South Korean defence ministry spokesman said they were monitoring developments but could not confirm if the submarine was designed to carry missiles.

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Mr Kim has declared a moratorium on testing ICBM’s and nuclear weapons while engaging in denuclearisation talks with the US and South Korea.

The submarine photos come amid another delay in dialogue between Washington and Pyongyang after Mr Kim and Donald Trump agreed at a meeting at the Panmunjom Korean border on 30 June to working-level nuclear talks.

Mr Trump said such talks could come in the following two to three weeks. His national security advisor, John Bolton, arrives in South Korea on Tuesday to meet security officials.

Kim Jong Un seen inspecting submarine at an unknown location in North Korea (AP)

HI Sutton, a naval analyst who studies submarines, said the latest photos indicated the hull could be based on old Romeo Class submarines, which were originally acquired from China in the 1970s before North Korea began producing them domestically.

North Korea is believed to have about 20 Romeo submarines in its fleet, the newest of which was built in the mid-1990s.

Mr Sutton said the North Koreans appeared to have raised the deck on a Romeo-type design, possibly even modifying an existing Romeo to make a submarine larger than previous designs.

“I’d bet that this is indeed a missile submarine,” he said.

US-based monitoring group 38 North said in June 2018 that North Korea appeared to be continuing submarine construction at its Sinpo Shipyard of possibly another Sinpo-class ballistic missile submarine, based on commercial satellite imagery.