The UK's decision to double its troops in Norway from 1,000 to 2,000 in the next three years comes as the US was set to relinquish two top regional NATO command posts to press allies to take greater responsibility for their defence.

"Arctic and High North security will be strengthened against rising Russian threats as Britain steps up its presence in the region," the UK Ministry of Defence said in a statement.

Defence Secretary John Healey is set to confirm on a visit to a UK military site in northern Norway that British forces will be involved in NATO's Arctic Sentry mission to bolster security in the region.

European members of the transatlantic alliance have scrambled to boost defences in the region after US President Donald Trump used alleged threats from Russia and China to justify his repeated threats to seize Greenland.

"Demands on defence are rising, and Russia poses the greatest threat to Arctic and High North security that we have seen since the Cold War," Healey said in a statement.

Diplomats confirmed over the weekend that Washington would hand over leadership of its Norfolk command, focusing on the alliance's north, to Britain.

The UK and Norway last December signed a new defence pact that would see their navies jointly operate a warship fleet to "hunt Russian submarines" in the North Atlantic.

That agreement aimed to protect critical undersea infrastructure such as communications cables, which Western officials say are increasingly under threat from Moscow.

Oslo also announced last year the purchase of at least five Type-26 frigates from Britain for pound10 billion ($13 billion).

In 2023, the UK opened a new military base called Camp Viking in the far north of Norway, which serves as a hub for Britain's Royal Marines.

Britain is planning to lead a Joint Expeditionary Force (JEF) of northern European and Baltic nations in "major military activity" in September.

The exercise called "Lion Protector" will see "air, land, and naval forces from JEF nations train to protect critical national infrastructure from attacks and sabotage."

A cross-party delegation of United States senators visited Greenland on Monday to "rebuild the trust" shattered by Trump's threats to annex the Danish territory, the lawmakers said.