"Germany and Norway aim to ensure stability and security in maritime areas, including in the High North," said a joint statement released as German Chancellor Friedrich Merz met with Norway's Prime Minister Jonas Gahr Store in Berlin.

The two countries also reaffirmed their "unwavering support for Ukraine as it defends its freedom, sovereignty, independence and territorial integrity against Russia's continued war of aggression."

Berlin and Oslo said that "the North Atlantic, including the strategically crucial Greenland-Iceland-United Kingdom (GIUK) and Bear gaps and adjacent waters, and the North and Baltic Seas, are crucial for both Norwegian and German security."

This, they said, was why their armed forces trained and patrolled the seas together and "cooperate closely under NATO's Regional Plans", the statement added.

During the Cold War, NATO kept close watch of the so-called GIUK gap, the key passageway for Soviet submarines and naval vessels from Arctic bases to enter the Atlantic Ocean.

Germany and Norway said they would strengthen their "surveillance and control over these strategic areas to counter potential threats, including maritime and airborne activities."

They also said that their cooperation in the North Atlantic and North Sea would include "enhanced protection of critical underwater infrastructure".