Kim Jong Un is captured walking around the submarine building site (Picture: KCNA).
Kim Jong Un has been pictured inspecting a newly built submarine, sparking concerns that North Korea is continuing to develop its ballistic missile programme.
A report published by the Korean Central News Agency (KCNA) said Mr Kim "expressed great satisfaction" with the submarine and its firepower.
KCNA quoted Mr Kim as saying "the operational capacity of a submarine is an important component in [the] national defence of our country bounded on its east and west by sea".
The report said the submarine's operational deployment is "near at hand" and it will operate in the East Sea.
KCNA also reported Mr Kim "stressed the need to steadily and reliably increase the national defence capability by directing big efforts" towards the development of naval equipment including submarines.
The state news agency did not mention any details about the submarine's capability or where it is being built.
Mr Kim's visit comes after North Korea said it may lift its 20-month suspension of nuclear and missile tests in protest over military exercises between the US and South Korea.
North Korea claims the drills are invasion rehearsals.
North Korea has repeatedly said it is willing to abandon its nuclear programme in return for the lifting of US-led sanctions.
However, there has been little progress since the latest Trump-Kim meeting.
Prior to talks with the US last year, North Korea claimed to have successfully test-fired ballistic missiles from submarines but some experts say the country remains years away from having an operational system.
According to a South Korean defence report in 2018, North Korea has 70 submarines and submersibles.