BRUSSELS/OSLO -  "If the US attacks another NATO country, everything stops," said Danish Prime Minister Mette Frederiksen on Monday.

In an interview with Danish broadcaster DR, the Danish prime minister made the remarks in response to a question as to what it would mean if the United States were to use force against another NATO member.

Frederiksen also slashed US President Donald Trump's renewed comments that the United States "needs" Greenland, denouncing his remarks as "unacceptable pressure" on the self-governing territory.

"Unfortunately, I think the American president should be taken seriously when he says he wants Greenland," she said, stressing that both Denmark and Greenland have repeatedly rejected any idea of Greenland becoming part of the United States.

She added that while she cannot account for US actions, "there is full support from Europe that borders must be respected."

European leaders have rallied behind Denmark after Trump again floated the idea of acquiring Greenland and called the Arctic territory critical to US defense.

"Borders cannot be changed by force," said French Foreign Ministry spokesman Pascal Confavreux in an interview with local media, expressing "solidarity" with Denmark.

Stressing Denmark's status as a NATO member, British Prime Minister Keir Starmer told the BBC, "The future of Greenland is for the Kingdom of Denmark and for Greenland themselves."

German Foreign Minister Johann Wadephul noted that Greenland, as part of Denmark, would in principle fall under NATO's collective defense obligations.

European leaders back Denmark 

European leaders have rallied behind Denmark after Trump again floated the idea of acquiring Greenland and called the Arctic territory critical to US defense.

"We do need Greenland, absolutely," Trump said in an interview with The Atlantic on Sunday. His comments came after American military action in Venezuela, heightening concerns in Europe that Greenland could be the next target of US intervention.

The remarks drew swift condemnation from Greenland and Denmark. Danish Prime Minister Mette Frederiksen said the United States has no right to annex Greenland and urged Washington to stop making threats against a close ally. Greenlandic Prime Minister Jens-Frederik Nielsen called the US rhetoric "completely and utterly unacceptable."

Nordic leaders were among the first to respond. Norwegian Foreign Minister Espen Barth Eide told public broadcaster NRK that "One must respect countries' sovereignty." Finnish President Alexander Stubb and Swedish Prime Minister Ulf Kristersson both stressed that decisions about Greenland rest solely with Denmark and Greenland, voicing their full support for their neighbor.

On Monday, Frederiksen escalated her warning, telling Danish broadcaster TV2 that a US takeover of Greenland would effectively end the NATO military alliance. "If the United States chooses to attack another NATO country militarily, then everything stops," she said, referring to the collective security framework established after the Second World War.

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More European countries echoed the position. Austrian Foreign Minister Beate Meinl-Reisinger wrote on X: "Greenland is an autonomous territory of the Kingdom of Denmark. Denmark has made it unequivocally clear: Threats and annexation fantasies are not acceptable."

French Foreign Ministry spokesman Pascal Confavreux said, "Borders cannot be changed by force," expressing "solidarity" with Denmark in an interview with the French public television channel TF1.

British Prime Minister Keir Starmer told the BBC that "the future of Greenland is for the Kingdom of Denmark and for Greenland themselves," while stressing Denmark's status as a NATO member.

German Foreign Minister Johann Wadephul noted that Greenland, as part of Denmark, would in principle fall under NATO's collective defense obligations.

Italian Foreign Minister Antonio Tajani urged the European Union (EU) to take a firm stance. "We'll see what Donald Trump's real intentions are on Greenland," he told Italian media RTL 102.5, adding that the EU must guarantee the independence of a territory under the Danish Crown.

At the EU level, European Commission spokesperson Anita Hipper said during a daily briefing that the bloc will continue to "uphold the principles of national sovereignty, territorial integrity, the inviolability of borders and the UN Charter." 

Greenlandic PM: US remarks utterly unacceptable

Greenlandic Prime Minister Jens-Frederik Nielsen said on Sunday night that the "immediate and repeated rhetoric" from the United States concerning Greenland is "completely and utterly unacceptable."

"Now it's enough," Nielsen said in a statement posted on Facebook, adding, "No more pressure. No more hints. No more fantasies about annexation."

He said that when the president of the United States talks about "we need Greenland" and connects Greenland with Venezuela and military intervention, it's wrong.

"Threats, pressure and talk of annexation do not belong anywhere between friends," Nielsen said.