The EU will discuss how to respond to a new wave of costly export barriers imposed on the bloc’s members by U.S. President Donald Trump, as the White House steps up its campaign to take control of Greenland from Denmark.

Trump’s imposition of a 10 percent tariff on NATO allies that have opposed his move against Greenland — including France, Germany, Denmark, the Netherlands, the U.K., Norway, Sweden and Finland — reopens a transatlantic trade rift that capitals thought had been averted by a deal signed last year.

Speaking after the signing of a landmark trade agreement between the EU and South American nations in Paraguay on Saturday, European Council President António Costa criticized Trump’s tactics as a threat to “prosperity,” saying “we must open markets, not close them. We must create zones of economic integration, not increase tariffs.”

“The European Union will always be very firm in defending international law, wherever it may be, and of course, starting within the territory of the European Union’s member states,” Costa said. “I am coordinating a joint response from the European Union’s member states on this issue.”

Trump announced the new tariffs in a post on his Truth Social site Saturday, claiming the countries targeted had sent military personnel to Greenland in recent days “for purposes unknown.” A small deployment of NATO troops landed in Greenland’s capital, Nuuk, on Thursday as part of a reconnaissance and support mission.

“The United States of America is immediately open to negotiation with Denmark and/or any of these countries that have put so much at risk,” Trump said, insisting Washington would complete its acquisition of Greenland. The 10 percent tariff will be increased to 25 percent on June 1, and will be enforced “until such time as a Deal is reached for the Complete and Total purchase of Greenland,” Trump said.

Three European diplomats, granted anonymity to speak about the response, told POLITICO that an extraordinary meeting of ambassadors to assess the situation and plan a response had not yet been called.

Costa, along with European Commission President Ursula von der Leyen and their top advisers, are together in Paraguay for the signing of the deal with Mercosur countries, from where the EU leadership is now actively reaching out to capitals, two officials confirmed. The Mercosur agreement has taken more than a quarter of a century to conclude and is being presented as a major effort to diversify trade ties in the context of Trump’s push against free commerce.

Reacting to the new tariffs, Swedish Prime Minister Ulf Kristersson said in a statement that European countries “will not let ourselves be blackmailed. … This is an EU issue that affects many more countries than those now being singled out. Sweden is now having intensive discussions with other EU countries, Norway, and the United Kingdom for a coordinated response.”