An annual report by the Danish defence intelligence service said security tensions were spreading to the Arctic, with Russia adopting a riskier approach and minimal international co-operation.

“Russia prioritises the region and will demonstrate strength through aggressive and threatening behaviour, which will entail a greater risk of escalation than previously seen in the Arctic,” the report said.

Russia is expected to reluctantly grant China greater access to the Arctic. China, in turn, is likely to use this access to bolster its role in the region and advance its plans to establish a military presence, the report said.

The Arctic is of considerable military strategic importance as a deployment area for nuclear-armed submarines, which can hide beneath the ice and, in the event of conflict, strike most of North America, Europe and Russia.

The route over the North Pole is also the shortest path between North America and Russia, making it likely that other ballistic missiles would fly over the North Pole towards their targets in a potential war scenario.

Greenland, a semi-autonomous part of Denmark, is home to the Pituffik air base, an essential component of the US ballistic missile early warning system.