Danish Prime Minister Mette Frederiksen on Monday said that a US takeover of Greenland would mean the end of the NATO military alliance.

On Tuesday, Frederiksen released a joint statement with the leaders of Germany, France, Italy, Poland, Spain and the UK reiterating that European allies were stepping up "to keep the Arctic safe and to deter adversaries."

It comes after US President Donald Trump renewed his calls for the large Arctic island, which is an autonomous territory of Denmark, to come under Washington's control.

What did Danish PM Frederiksen say?

Frederiksen said that "everything would stop" when it comes to cooperation with Washington in the event of a US attack on another NATO member.

"If the United States decides to attack another NATO country, then everything would stop — that includes NATO and therefore post-World War II security," Frederiksen said.

Meanwhile, Greenland's prime minister, Jens-Frederik Nielsen, called for the territory to restore "good cooperation" with the United States and urged Greenlanders not to "panic."

"The situation is not such that the United States can conquer Greenland. That is not the case. Therefore, we must not panic. We must restore the good cooperation we once had," Nielsen said while speaking in Greenland's capital, Nuuk.

In a social media post on Monday, he called for Trump to give up "fantasies" of annexing Greenland.

"That's enough now. No more pressure. No more insinuations. No more fantasies of annexation." "We are open to dialogue," he said. "But this must happen through the proper channels and with respect for international law."

European leaders back Denmark

In a joint statement with Frederiksen, French President Emmanuel Macron, German Chancellor Friedrich Merz, Italian Prime Minister Meloni, Polish Prime Minister Donald Tusk, Spanish Prime Minister Pedro Sanchez and British Prime Minister Keir Starmer expressed support for Denmark and Greenland. 

"Arctic security remains a key priority for Europe and it is critical for international and transatlantic security," the joint statement read. 

"We and many other Allies have increased our presence, activities and investments, to keep the Arctic safe and to deter adversaries," it added. 

The seven leaders stressed that Washington "is an essential partner in this endeavour."

Why does Trump want Greenland?

On Sunday, Trump reiterated his view that Greenland should come under the control of the United States a day after Venezuelan President Nicolas Maduro was captured in a US incursion and taken to New York to stand trial.

"We need Greenland," Trump told journalists on Sunday, stressing that this was necessary for Washington's "national security" and claiming that the island was surrounded "by Chinese and Russian ships."

Trump has in the past offered to buy the territory, while not ruling out the use of military force to take it over.

Greenland has large quantities of oil, critical minerals and other resources. The territory could also gain economic importance in coming decades as new Arctic shipping routes open due to the melting of polar ice.

Greenland already hosts a US military base, and Copenhagen has expressed willingness to allow for the deployment of additional US troops.

On Monday, top Trump adviser Stephen Miller described Greenland as "a colony of Denmark," adding "nobody's going to fight the United States militarily over the future of Greenland."

Edited by: Roshni Majumdar