North Korean leader Kim Jong-un has called for strengthening the country's navy to step up war preparations and protect maritime sovereignty during a visit to a shipyard for warships, state media said Friday.

Kim made the remarks as the North has been dialing up tensions on the Korean Peninsula in the new year -- an election year for South Korea and the United States -- with weapons tests and harshly worded rhetoric.

North Korea recently conducted three cruise missile launches in a week, including a new submarine-launched strategic cruise missile, named the "Pulhwasal-3-31."

During his visit to the Nampho Dockyard, Kim stressed that bolstering the country's naval force is the "most important issue" that also calls for the modernization of the North's shipbuilding industry, the Korean Central News Agency said. It did not elaborate on when Kim's visit took place.

Kim was briefed on ongoing preparations to build warships and ordered officials to "unconditionally" push ahead with a five-year military development plan put forth during a party congress in 2021, according to the KCNA.

During the key meeting, Kim had vowed to develop high-tech weapons, including a nuclear-powered submarine, along with a hypersonic warhead, spy satellite and solid-fuel intercontinental ballistic missiles.

While the Sinpo South Shipyard, located in the eastern namesake city, is considered the North's main submarine shipyard, construction of a barge for launching SLBMs has been observed at Nampho Dockyard. (Yonhap)