European officials intensified warnings on Monday that a U.S. military takeover of Greenland would effectively end the NATO alliance and severely damage transatlantic relations.
The remarks come as Denmark and the United States, both NATO members, prepare for talks this week amid rising tension over the strategically located Arctic territory.
Greenland is an autonomous part of the Kingdom of Denmark and has repeatedly said it is not for sale.
U.S. President Donald Trump has argued that Washington must own Greenland to prevent Russia or China from occupying it, saying an existing U.S. military presence is insufficient.
Speaking at a security conference in Sweden, European Commissioner for Defence and Space Andrius Kubilius said the European Union could assist in securing Greenland if Denmark requested support.
He warned that a U.S. military occupation would have far-reaching political and public consequences across Europe.
"I agree with the Danish prime minister that it will be the end of NATO, but also among people it will be also very, very negative," Kubilius said.
He added that such an action would deeply harm trust between Europe and the United States.
Kubilius said he did not believe an invasion was imminent but stressed that EU treaty obligations require member states to assist Denmark if it faced military aggression.
He also questioned who would recognize any occupation and warned of potential fallout across trade and diplomatic relations.
Kubilius said the EU could deploy troops, warships, or anti-drone systems to Greenland if asked, noting that Arctic defense needs would be assessed by military planners.
His comments align with Danish Prime Minister Mette Frederiksen, who has said an attack on a NATO ally would halt the alliance’s functioning.
Trump, responding separately on social media, said "I'm the one who SAVED NATO!!!" without elaboration.
NATO Secretary General Mark Rutte has sought to play down the crisis, insisting the alliance is not collapsing.
EU diplomats cited by Politico said they doubted the U.S. would use force but believed pressure could lead to an expanded European military role in Greenland.
Kubilius said Europe must continue strengthening its own defense capabilities, warning that NATO in its current form could not survive a U.S. withdrawal.