"Let me be clear: we want strong transatlantic ties. The US will remain Europe's partner and ally. But Europe needs to adapt to the new realities. Europe is no longer Washington's primary centre of gravity," Kallas told a defence conference in Brussels.

"This shift has been ongoing for a while. It is structural, not temporary. It means that Europe must step up -- no great power in history has outsourced its survival and survived."

Trump rocked European allies this month by threatening to seize Greenland from NATO and EU member Denmark -- before eventually backing off.

The crisis -- the latest to buffet ties since his return to power a year ago -- has reinforced calls for the continent to cut its decades-long reliance on NATO's dominant military superpower for protection.

Kallas remained clear-eyed that NATO remains the bedrock of European security.

She said EU efforts should "remain complementary" to those of the alliance, but insisted Europe needed to play a bigger role.

"Especially now, as the US is setting its sights beyond Europe, NATO needs to become more European to maintain its strength," she said.

"For this, Europe must act."

European countries have already ramped up defence budgets since Russia invaded Ukraine four years ago, and agreed last year to massively hike NATO's spending target under pressure from Trump.

The EU last year also launched a raft of initiatives that it says could see its members plough an additional 800 billion euros into defence.

Washington meanwhile has said it wants European allies to take over more responsibility for the conventional defence of the continent as US focus switches to other threats like China.

"The risk of a full-blown return to coercive power politics, spheres of influence and a world where might makes right, is very real," Kallas said.

She insisted Europe "must acknowledge that this tectonic shift is here to stay. And to act with urgency."

Kallas' comments come after NATO chief Mark Rutte told EU lawmakers to "keep on dreaming" if they thought Europe could defend itself without the United States.

In a Monday address to the bloc's parliament, Rutte insisted that Europe would have to double its spending targets to afford the "billions and billions of euros" it would cost to replace the US nuclear umbrella.

The head of the Western military alliance also warned that if Europe tried to build its own forces to replace the United States in NATO then it would play into Russian leader Vladimir Putin's hands.

"Putin will love it. So think again," Rutte said.

Instead he urged the EU to use its traditional strengths to generate funding and cut regulation to help the defence industry grow.