Asked in a news conference if she saw a need to redefine Brussels's approach to Washington, as it has already done towards Beijing, von der Leyen said the answer was "a clear no -- it's a completely different relationship that we have with the United States than we have with China".

"Of course the US are allies," she told reporters in Brussels.

"Yes, there are differences... but if you look at the common interests that we have, they always outweigh our differences," she said, adding: "We will have our differences. We have to sort them out."

Trump has repeatedly threatened to slap tariffs on the European Union, and his alignment with Russia on Ukraine has deeply unsettled European officials. The US leader has also thrown up questions about US security commitments to Europe under the NATO umbrella.

Von der Leyen, speaking in general terms, stated that in the world today "everything has become transactional".

There was a growing sense of urgency within the 27-nation EU because "something fundamental has shifted. Our European values -- democracy, freedom, the rule of law -- are under threat," she said.

"The world around us is changing at lightning speed. Geopolitical shifts are shaking alliances. Decade-old certainties are crumbling."

When questioned specifically about the future of the transatlantic relationship with the United States, von der Leyen said that, while an allied bond persisted, "this does not mean that the pattern that we had the last... 25 to 30 years... is still the right one".

She stated that the changing tone of US ties was "a very strong wake-up call, and Europe's moment now really (is) to step up in defence and giving ourselves the posture that we need".

The bloc has already sent a clear signal it is moving in that direction, with an EU summit on Thursday agreeing to mobilise about 800 billion euros ($860 billion) to boost defence spending, which has long been urged by Washington, the EU chief said.

"We are allies, but this means that all allies have to take their responsibilities," she said.

Von der Leyen added that, within the "next weeks", she would call the bloc's first-ever meeting of EU commissioners focused on "external and internal security, to energy, defence and research" and including cybersecurity, trade and "foreign interference".