President Donald Trump's threats against Denmark's autonomous Arctic territory last month plunged the 76-year-old transatlantic alliance into its deepest crisis in years, before he abruptly backed off.

As part of a package to assuage Trump -- who based his demands for the island on an alleged threat by Russia and China -- NATO announced Wednesday the start of an Arctic Sentry mission to increase security in the region.

Dutch Defence Minister Ruben Brekelmans said he was "fully confident that this will also meet the concerns of the United States" at a meeting with counterparts from the 32-nation alliance in Brussels.

But while Europe breathed a sigh of relief about the apparent passing of that storm, the Greenland crisis has only reinforced for many the urgent need for Europe to take a greater role in NATO and its own defence in the face of the menace from Russia.

That is the message being sent by the Trump administration as well: that Europe needs to step up as Washington pivots to focus on other challenges such as China.

US deputy defence minister Elbridge Colby said that allies were making strides towards a situation where it is "Europe that leads the conventional defense of NATO" rather than traditionally relying on US military might.

"I think we have a really strong basis for working together in partnership," he said at the alliance's Brussels headquarters. "Kind of a 3.0 NATO that's based on a partnership rather than dependency."

- 'Expect more' -

To make good on plans for Europe to play a bigger role, NATO needs to make strides on fulfilling the pledge made at its summit last year for countries to massively ramp up defence spending.

Military budgets have already increased since Russia's 2022 invasion of Ukraine and Trump has spurred on that trend.

"The good news is that the billions are coming in," said NATO boss Mark Rutte.

Rutte however insisted that he believed the United States would continue to play a central role in defending Europe.

"I predict that longer term, you will see, of course, the nuclear umbrella as the ultimate guarantor of our security here in Europe and Canada, but also a strong conventional presence of the US here in Europe," he said.

In a concrete sign of Europe taking more responsibility within NATO, the alliance this week announced the United States was handing two senior regional command positions to Britain and Italy.

The move was heralded by diplomats as a sign of increased "burden-sharing" within the alliance in action.

French Defence Minister Catherine Vautrin referred to a demand several months back from Pentagon chief Pete Hegseth that Europeans must be able to ensure their own security.

"Well, we are going to do it, we have started to do it," she said.

The next crucial staging post will be the NATO summit in Ankara this July when allies will have to convince Trump that they are already doing enough.

"We'll receive our first full report on allied defence spending," the NATO US ambassador Matthew Whitaker said this week.

"We still have some allies that need to step up, particularly those geographically further from NATO's eastern flank. They're not moving as fast as they should, and we really expect them to do more."