President of the European Commission Ursula von der Leyen talks during the Annual Meeting of the World Economic Forum in Davos, Switzerland, Tuesday. (AP Photo/Markus Schreiber)

WASHINGTON (AP) — President Donald Trump ‘s pledge to provoke a sweeping tariff fight with Europe to get his way in taking control of Greenland has left many of America’s closest allies warning of a rupture with Washington capable of shattering the NATO alliance that had once seemed unshakable.

The European Union’s top official on Tuesday called Trump’s planned new tariffs over Greenland a “mistake” and questioned Trump’s trustworthiness. French President Emmanuel Macron said the EU could retaliate by deploying one of its most powerful economic tools, known colloquially as a trade “bazooka.”

Trump prides himself on ratcheting up pressure to try to negotiate through a position of strength. He was leaving Tuesday — the anniversary of his inauguration — for the World Economic Forum in Davos, Switzerland, a venue that offers Trump the chance to defuse tensions as quickly as he stirred them up.

But European leaders — digging in and vowing to defend Denmark and its control over semiautonomous Greenland — may be seeking just as hard to meet an extraordinary moment with a show of their fierce resolve.

That could hurt the chances of Trump finding a quick way to turn around the crisis. Greenland’s leader insisted on respect for its territorial integrity and said recognition of international law is “not a game.”

Trump made an unusual appearance in the White House briefing room to mark the one year he’d been in office. When asked how far he’d be willing to go to acquire Greenland, Trump said only, “You’ll find out.” He also mistakenly referred to Greenland as Iceland at one point.

Still, the president predicted there could be a deal in the making with allies. “I think that we will work something out where NATO is going to be very happy, and where we’re going to be very happy,” he said, without providing specifics.

Trump said he’d been encouraged that NATO had increased military spending, but he also belittled the alliance, saying other members may not protect Washington’s interests. The president suggested NATO members expect the U.S. to come to their rescue but “I just really do question whether or not they’ll come to ours.”

European Commission President Ursula von der Leyen pushed back against Trump’s announcement that, starting February, a 10% import tax will be imposed on goods from eight European nations that have rallied around Denmark. Greenland is a semiautonomous territory of Denmark, a NATO member.

“The European Union and the United States have agreed to a trade deal last July,” von der Leyen said in Davos. “And in politics as in business – a deal is a deal. And when friends shake hands, it must mean something.”

“We consider the people of the United States not just our allies, but our friends. And plunging us into a downward spiral would only aid the very adversaries we are both so committed to keeping out of the strategic landscape,” she added.

She vowed that the EU’s response “will be unflinching, united and proportional.”

Taking firmer stances defied the approach that many European leaders have offered since Trump returned to office. It had mostly entailed saying nice things about the president to try to stay in his good graces, while working furiously through other avenues to find compromise.

Trump says the U.S. needs Greenland to deter possible threats from China and Russia. But his continued insistence in recent weeks that anything short of the U.S. owning Greenland is unacceptable is testing the limits of the softer strategy.

Danish Prime Minister Mette Frederiksen said “the worst may still be ahead of us.” Speaking to parliament, she said “we have never sought conflict. We have consistently sought cooperation.”

‘Not a game’

Greenland’s Prime Minister Jens-Frederik Nielsen said at a news conference in the island’s capital, Nuuk, that “we need to have respect for international law and territorial integrity.” He said those principles should unite Western democratic countries, and expressed gratitude for EU allies’ support.

“International law, it’s not a game,” he said, adding, “We are willing to cooperate much more, but of course in mutual respect, and if we cannot see that, it will be very difficult to have a good and reliable partnership.”

Trump’s threats have sparked outrage and a flurry of diplomatic activity across Europe, as leaders consider possible countermeasures, including retaliatory tariffs and the unprecedented use of the EU’s anti-coercion instrument.

Unofficially known as the “trade bazooka,” the anti-coercion instrument could sanction individuals or institutions found to be putting undue pressure on the EU. The EU has two other major economic tools it could use to pressure Washington: new tariffs, or a suspension of the U.S.-EU trade deal.