Frederiksen and her Greenlandic counterpart, Jens Frederik Nielsen, blasted the president’s comments and warned of catastrophic consequences. Numerous European leaders expressed solidarity with them.

“If the United States chooses to attack another NATO country militarily, then everything stops,” Frederiksen told Danish broadcaster TV2 on Monday. “That is, including our NATO and thus the security that has been provided since the end of the Second World War.”

Trump called repeatedly during his presidential transition and the early months of his second term for U.S. jurisdiction over Greenland, and has not ruled out military force to take control of the island. His comments Sunday, including telling reporters “let’s talk about Greenland in 20 days,” further deepened fears that the U.S. was planning an intervention in Greenland in the near future.

Frederiksen also said Trump “should be taken seriously” when he says he wants Greenland. “We will not accept a situation where we and Greenland are threatened in this way,” she added.

Nielsen, in a news conference Monday, said Greenland cannot be compared to Venezuela. He urged his constituents to stay calm and united.

“We are not in a situation where we think that there might be a takeover of the country overnight and that is why we are insisting that we want good cooperation,” he said.

Nielsen added: “The situation is not such that the United States can simply conquer Greenland.”

Ask Rostrup, a TV2 political journalist, wrote on the station’s live blog Monday that Mette previously would have flatly rejected the idea of an American takeover of Greenland. But now, Rostrup wrote, the rhetoric has escalated so much that she has to acknowledge the possibility.

Trump on Sunday also mocked Denmark’s efforts at boosting Greenland’s national security posture, saying the Danes have added “one more dog sled” to the Arctic territory’s arsenal.

“It’s so strategic right now,” Trump had told reporters Sunday as he flew back to Washington from his home in Florida. “Greenland is covered with Russian and Chinese ships all over the place.”

He added: “We need Greenland from the standpoint of national security, and Denmark is not going to be able to do it.”

But Ulrik Pram Gad, a global security expert from the Danish Institute for International Studies, wrote in a report last year that “there are indeed Russian and Chinese ships in the Arctic, but these vessels are too far away to see from Greenland with or without binoculars.”

Greenlanders and Danes were further rankled this weekend by a social media post following the raid by a former Trump administration official turned podcaster, Katie Miller. The post shows an illustrated map of Greenland in the colors of the Stars and Stripes accompanied by the caption: “SOON.”

“And yes, we expect full respect for the territorial integrity of the Kingdom of Denmark,” Ambassador Jesper Møller Sørensen, Denmark’s chief envoy to Washington, said in a post responding to Miller, who is married to Trump’s influential deputy chief of staff Stephen Miller.

The U.S. Department of Defense operates the remote Pituffik Space Base in northwestern Greenland. It was built following a 1951 defense agreement between Denmark and the United States. It supports missile warning, missile defense and space surveillance operations for the U.S. and NATO.

On Denmark’s mainland, the partnership between the U.S. and Denmark has been long-lasting. The Danes buy American F-35 fighter jets and just last year, Denmark’s parliament approved a bill to allow U.S. military bases on Danish soil.

Critics say the vote ceded Danish sovereignty to the U.S. The legislation widens a previous military agreement, made in 2023 with the Biden administration, where U.S. troops had broad access to Danish air bases in the Scandinavian country.