Kim Jong-un calls for naval reinforcement amid missile tests off North Korea's western coast

"Strengthening the naval forces is currently the most vital task in credibly defending the country's maritime sovereignty and escalation of war preparations," Kim said, as reported by North Korea's news agency KCNA.

According to state media, the North Korean leader visited the port city of Nampo to review the construction of new warships.

On Friday morning, Eastern Time, the South Korean military reported detecting "several unidentified manoeuvring missiles" on the western coast of North Korea. The army is continuing the analysis of collected data.

It's another incident from North Korea within the month. In mid-January, the army conducted tests with underwater drones capable of carrying nuclear weapons. In early January, tests were conducted involving supersonic missiles with medium and long-range capabilities.

The AFP agency points out that last year, North Korea declared that its navy had commissioned its first nuclear-powered submarine. However, South Korean experts cast doubt on whether the vessel is actually in active service. North Korea's focus on the development of a submarine fleet was further highlighted during Sunday's missile test, which aimed to launch manoeuvring missiles from a submarine.