The EU needs to be more clear-eyed on the world stage in the face of US President Donald Trump's "America First" policies and other rival powers, European Commission chief Ursula von der Leyen said Tuesday.

"Europe must deal with the world as we find it," von der Leyen said in a speech to EU ambassadors.

"It must make decisions not out of emotion or nostalgia for a world that once was, but rather out of calculated judgement about what is in our own interest in the world as it is today."

The 27-nation bloc is grappling with the return of Trump to the White House as he takes an uncompromising approach with Washington's traditional allies.

The US president fired a first salvo by announcing tariffs on key partners Canada and Mexico — before suspending the measures after getting promises of more border controls. 

Trump has warned that the European Union could be his next target, leaving member states bracing for cut-throat talks. 

"We need to engage. We might have to engage in tough negotiations, even with long-time partners," von der Leyen said. 

"And we might also have to work with countries that are not like-minded but do share some of our interests."

The commission president told the bloc's envoys "the basic principle of diplomacy in this new world is to keep our eyes on the goal."

"That means, finding common ground with partners to our mutual benefit — and accepting that on occasion we will have to agree to disagree," she said. 

EU leaders, who met in Brussels on Monday, warned Trump that they were willing to hit back against any tariffs — even as they hoped to prevent them. 

Von der Leyen echoed those assertions as she said "Europe will safeguard its economic and national security." 

"But it is also important that we strike the right balance," she said.

"We want to avoid a global race to the bottom that is in no one's interests."

Brussels has stepped up trade ties with other parts of the globe, recently striking new agreements with South American countries, Mexico and Switzerland.

Von der Leyen said this push would continue, including with increased outreach to India and a summit with South Africa. 

The EU chief insisted that Europe's priority remained supporting Ukraine as Russia's war reaches the three-year mark.

She said the bloc would start looking to see how it could make greater use of hundreds of billions of dollars of frozen Russian assets. 

"We must show to the Kremlin that the longer the war, the higher the price for Russia. Ukraine needs peace through strength," she said.