Europe must step up urgently to improve its defence and make NATO more European to maintain its strength, because the US has shaken the transatlantic relationship to its foundation, the EU's foreign policy chief has warned.

The US would continue to be Europe's partner and ally, Kaja Kallas told a defence conference, but no great power had ever outsourced its survival and survived.

Tensions with the US flared when President Donald Trump threatened to take over Greenland, a semi-autonomous Danish territory.

Kallas's remarks came after NATO leader Mark Rutte prompted a backlash when he said European lawmakers should keep on dreaming if they thought Europe could defend itself without the US.

French Foreign Minister Jean-Noël Barrot reacted to the secretary-general's comments, asserting that Europeans can and must take control of their security. Even the United States agrees. It's the European pillar of NATO.

Kaja Kallas stated that under the Trump administration, Europe was no longer Washington's primary centre of gravity and stressed the need to shift from national to joint European action.

Washington's transition away from Europe has been ongoing for a while, she noted, describing it as a structural shift rather than a temporary one.

The 23 nations that are members of both the EU and NATO have a special responsibility to coordinate efforts, Kallas indicated, emphasizing the significance of establishing a distinct European defense capability.

The recent US-European rift regarding Greenland has underscored a tectonic shift in their relationship, especially as Trump threatened to impose tariffs on allies opposing his plans for the Arctic island.

Mark Rutte was praised last week for easing tensions when Trump moderated his stance during discussions at the World Economic Forum in Davos.

Under pressure from Trump, NATO member states promised to boost their defense spending to 5% of GDP by 2035, although some of that could finance national infrastructure.

Rutte warned that if Europe sought to go it alone on defence, it would require spending 10% of GDP and establishing its nuclear capabilities.

Rutte raised concerns that distancing from the US would mean losing the assurance provided by the US nuclear umbrella.

At the same conference, EU Defence Commissioner Andrius Kubilius remarked that the US now expects Europeans to take responsibility for their defence as the American presence on the continent diminishes.

Describing Europe as a giant, but a sleeping giant, Kubilius called for rapid steps toward building independence in defense.

NATO was founded in 1949 to secure the freedom of its members against a hostile Soviet Union, which collapsed in 1991.

As relations with Russia grow increasingly tenuous, recent EU members Sweden and Finland have joined NATO, accentuating a united front against military expansionism.

The Kremlin's demand that a future peace deal exclude Ukraine from NATO membership reflects ongoing geopolitical tensions, as Ukraine's aspiration to join NATO remains uncertain.