"All the United States is asking for is a place called Greenland, where we already had it as a trustee, but respectfully returned it back to Denmark not long ago," Trump said.

The president's push to gain control of Greenland, a Danish territory, has created anxiety about the future of the alliance throughout Europe.

In supermarkets and on shopping streets across Denmark, a quiet form of protest is unfolding at the checkout line. Shoppers are turning to barcode scanners on their phones to steer clear of American-made goods,

Negotiators have discussed proposals to check Russian and Chinese influence in the Arctic and transfer sovereignty over pockets of Greenlandic land to the United States, an idea opposed by Denmark.

During a speech Wednesday at the World Economic Forum in Davos, Switzerland, President Trump said that he would not use force to take Greenland, an island the State Department says the United States needs to control to counter threats in the surrounding Arctic sea by Russia and China.

Since Russia full-scale invasion of Ukraine almost four years ago, Europe's attention has been firmly fixed on NATO's eastern flank. But could the Arctic become the next area requiring defence and does Bundeswehr have the capacity to take on that role?

Trump’s envisioned multilayered “Golden Dome” could include space-based sensors to detect missiles. They could reduce the U.S. need for its Greenland-based radar station, said Marcuz, a former nuclear defense worker for France’s Defense Ministry, now with the Foundation for Strategic Research think tank in Paris.

Using the price at which Russia sold Alaska to the US as a reference and accounting for price adjustments, Putin said buying Greenland from Denmark could cost around $1 billion.