Nuuk, Greenland. US President Donald Trump said Saturday that he would charge a 10% import tax starting in February on goods from eight European nations because of their opposition to American control of Greenland.

Trump said in a social media post that Denmark, Norway, Sweden, France, Germany, the United Kingdom, the Netherlands, and Finland would face the tariff and that it would climb to 25% on June 1 if a deal is not in place for “the Complete and Total purchase of Greenland” by the United States.

The threat of tariffs was a drastic and potentially dangerous escalation of a showdown between Trump and NATO allies, further straining an alliance that dates to 1949 and provides a collective degree of security to Europe and North America. The Republican president has repeatedly tried to use trade penalties to bend allies and rivals alike to his will, generating investment commitments from some nations and pushback from others such as China, Brazil, and India.

It was unclear how Trump could impose the tariffs under US law, though he could cite economic emergency powers that are currently subject to a US Supreme Court challenge.

Trump said in his Truth Social post that his tariffs were retaliation for recent trips to Greenland by representatives from Britain, the Netherlands, and Finland, and for general opposition to his efforts to purchase the semiautonomous territory of NATO ally Denmark. He has said Greenland is essential for the “Golden Dome” missile defense system for the US, and has argued that Russia and China might try to take over the island.

Resistance has steadily built in Europe to Trump's ambitions, even as several countries on the continent agreed to his 15% tariffs last year in order to preserve an economic and security relationship with Washington.

Earlier Saturday, hundreds of people in Greenland's capital braved near-freezing temperatures, rain, and icy streets to march in a rally in support of their own self-governance.

The Greenlanders waved their red-and-white national flags and listened to traditional songs as they walked through Nuuk's small downtown. Some carried signs with messages like “We shape our future,” “Greenland is not for sale” and “Greenland is already GREAT.” They were joined by thousands of others in rallies across the Danish kingdom.

The rallies occurred hours after a bipartisan US congressional delegation in Copenhagen sought to reassure Denmark and Greenland of their support.

NATO Training Exercises
Danish Maj. Gen. Søren Andersen, leader of the Joint Arctic Command, told The Associated Press that Denmark doesn't expect the US military to attack Greenland, or any other NATO ally, and that European troops were recently deployed to Nuuk for Arctic defense training.

He said that the goal isn’t to send a message to the Trump administration, even though the White House hasn’t ruled out taking the territory by force.

“I will not go into the political part, but I will say that I would never expect a NATO country to attack another NATO country,” he told the AP on Saturday aboard a Danish military vessel docked in Nuuk. “For us, for me, it’s not about signaling. It is actually about training military units, working together with allies.”

The Danish military organized a planning meeting on Friday in Greenland with NATO allies, including the US, to discuss Arctic security on the alliance’s northern flank in the face of a potential Russian threat. The Americans were also invited to participate in Operation Arctic Endurance in Greenland in the coming days, Andersen said.

In his 2½ years as a commander in Greenland, Andersen said that he hasn't seen any Chinese or Russian combat vessels or warships, despite Trump saying that they were off the island's coast.

But in the unlikely event of American troops using force on Danish soil, Andersen confirmed a Cold War-era law governing Danish rules of engagement.

“But you are right that it is Danish law that a Danish soldier, if attacked, has the obligation to fight back,” he said.

Thousands of people marched through Copenhagen, many of them carrying Greenland’s flag. Others held signs with slogans like “Make America Smart Again” and “Hands Off.”

“This is important for the whole world,” Danish protester Elise Riechie told the AP as she held Danish and Greenlandic flags. “There are many small countries. None of them are for sale.”

Trump has sought to justify his calls for a US takeover by repeatedly saying that China and Russia have their own designs on Greenland, which holds vast untapped reserves of critical minerals.

“There are no current security threats to Greenland,” Coons said.

Trump has insisted for months that the US should control Greenland, and said earlier this week that anything less than the Arctic island being in US hands would be “unacceptable.”

During an unrelated event at the White House about rural health care, he recounted Friday how he had threatened European allies with tariffs on pharmaceuticals.

“I may do that for Greenland, too,” Trump said.

He had not previously mentioned using tariffs to try to force the issue.