EU chief promises 'unflinching' response to new tariffs as Trump trolls and threatens on social media

European Commission President ​Ursula von der Leyen said ​on Tuesday the EU shared concerns with the United States about Arctic security, but if President Donald Trump followed through with new tariffs based on a dispute over Greenland, the alliance's response would be "unflinching" and "united."

Von der Leyen, speaking at the World Economic Forum in Davos, Switzerland, said the U.S. risks sending its relationship with EU allies "into a downward spiral" that would only benefit shared adversaries.

Trump announced planned tariffs this weekend on eight countries that sent small numbers of ‍military personnel to Greenland last week, following the U.S. president's repeated statements that he wanted to take over Denmark's vast Arctic island. The Trump administration has talked about acquiring Greenland, and some White House officials have stated that military options were not being ruled out to seize the island.

Those statements have continued even in the face of sustained resistance and negativity from Greenland and Denmark and its allies, and public polling in the U.S. has indicated Trump's ambitions may not be shared by a majority of Americans.

Trump said the tariffs of 10 per cent would go into effect on Feb. 1 and rise to 25 per cent on June 1.

"In politics as in business — a deal is a deal and when friends shake hands, it must mean something," said von der Leyen, referring to the trade deal the EU and U.S. struck last summer.

Trump's threats have sparked outrage and a flurry of diplomatic activity across Europe, as leaders consider possible countermeasures, including retaliatory tariffs and the first-ever use of the European Union's anti-coercion instrument. While it would have to be agreed by at least 15 member states and take months to implement, that never-before-used tool restricts access to EU services, investments and public procurement.

The U.S. president shared several bellicose social media posts early Tuesday, and said there was "no going back" on his goal to control Greenland. One post Trump shared including a picture of a meeting with European leaders last year at the Oval Office, but with what appears to be an edited map on display in which the land masses of Canada and Greenland are depicted with American stars and stripes.

Another post seemed designed to damage French President Emmanuel Macron, who has clashed with Trump on Greenland and turned down his request to join a board to oversee the reconstruction of Gaza. Trump shared a screenshot of a private message between the leaders, wherein Macron told Trump he did not ​understand what the U.S. president was "doing on Greenland."

Trump's replies to Macron, if they existed, were ‍not part of ⁠the screenshot that he posted on his Truth ​Social account early on Tuesday.

Macron, speaking in English while addressing a Davos audience, said that Europeans "prefer respect to bullies" and that it was staggering the ⁠bloc even had to consider ​using its anti-coercion instrument against the U.S.

"Europe has very strong tools now, and we have to use them when we are not respected, and when the rules of the game are not respected," said Macron.

Trump said in another post he had spoken to NATO Secretary General Mark Rutte and that he would meet with unspecified European leaders this week in Davos.

Separately, the EU is holding a meeting on Greenland on Thursday in Brussels.