Kim Jong-un, the North Korean leader, has inspected a new submarine, potentially signalling continued development of a submarine-launched ballistic missile (SLBM) programme.

North Korean state media has released images of Mr Kim admiring the submarine in a covered fabrication building. The reports have not identified the location of the facility, but satellite images in recent months have shown the construction of new facilities at the Sinpo South Shipyard, on the east coast, and components being stockpiled nearby.

The Korean Central News Agency reported that Mr Kim expressed “great satisfaction” after being informed to the vessel’s capabilities, and that it will “perform its duties in the operational waters of the East Sea of Korea, and its operational deployment is near at hand”.

The North Korean dictator also “stressed the need to steadily and reliably increase the national defence capability” through the development of naval weapons.

The release of the photographs coincides with the arrival in Tokyo of John Bolton, the US national security adviser, and is likely to be a signal to Washington that Pyongyang is continuing to develop its military capabilities in the face of international sanctions.

“It’s a typical North Korean tactic; to talk tough and to show that they are not intimidated by the US, that they don’t care that Bolton is in the region and that they are going to continue to take a hard line,” said Robert Dujarric, a professor of international relations at the Tokyo Campus of Temple University.