President Donald Trump has signed an agreement with Denmark and Greenland aimed at strengthening Arctic and North Atlantic security, which eases tensions over his repeated calls for Greenland to become part of the United States.

The signing on Tuesday, which took place on the sidelines of the U.N. General Assembly in New York, comes just days after Trump announced the deal to strengthen the U.S. military presence on the vast, icy island while keeping it under Danish control.

"This is tremendous for Europe and for the United States and for everybody," Trump said just before the agreement was signed.

"And for Greenland, it's going to be incredible."

For months, Trump has articulated his aspiration for Greenland to be incorporated into the United States and has issued threats to seize the semiautonomous territory from Denmark, a NATO ally.

On Tuesday, he did not respond to questions as to whether a U.S. acquisition of Greenland had been ruled out.

For months, officials from the U.S., Greenland and Denmark engaged in behind-the-scenes negotiations, endeavoring to devise solutions that might address some of Trump’s security concerns regarding the mineral-rich island.

Trump's designs on Greenland strained relations within NATO, with Danish Prime Minister Mette Frederiksen warning that a U.S. takeover would mean the end of the Atlantic alliance.

The standoff unsettled many of Greenland's roughly 56,000 people and created a rift between the United States and Denmark, as well as its European Union partners, who increased their security exercises on the island and their monetary support for it.

Trade and hopes for a resource grab have all factored into concerns about Greenland's future: roughly two-thirds of its territory lies within the Arctic Circle, where melting sea ice has opened up additional shipping routes

For decades, the United States had a prominent presence in Greenland, but since 1945, the U.S. military presence there has decreased from thousands of soldiers on 17 bases and installations to roughly 200 soldiers on the remote Pituffik Space Base in the northwest.

The base supports missile warning, missile defense, and space surveillance operations for the U.S. and NATO.

In an address to the United Nations General Assembly on Tuesday morning, Trump offered a glimpse into the specifics of the deal.

"We will immediately commence the process of establishing a substantial military presence in the appropriate locations," he said, including "constructing two exceedingly major military bases."

Denmark’s parliament approved a bill last year to allow U.S. military bases on Danish soil, widening a 2023 military agreement made with the Biden administration that gave U.S. troops broad access to air bases in Denmark.

Trump had previously asserted that the United States needed to “take Greenland,” in order to preclude Russia or China from doing likewise.

Although Trump remarked that he would prefer to “make a deal” for the territory, he appended: “one way or the other, we’re going to have Greenland.”

The agreement, which the Danish government released after the signing, permits Washington to “modernize and expand” its activities at the Pituffik Space Base in northwest Greenland.

It also states that the U.S. can establish “defense areas” at Narsarsuaq in the south and Mestersvig in the east, and that it “may establish additional defense areas in Greenland and strengthen its military operations or facilities.”

Washington is to award contracts for goods and services related to setting up, maintaining or dismantling such bases “to Greenlandic sources to the maximum extent possible.”

The accord calls for extensive U.S. military mobility across Greenland's territory, including "undersea access."

No non-NATO country will be permitted to establish "its own manned or unmanned military installations in Greenland," nor to maintain a "persistent" military presence, unless the signatories agree otherwise.

The accord “does not have an end date,” and if Greenland chooses to become independent, it will agree to remain in NATO and take on Denmark’s rights and obligations under the deal.

Mikkel Runge Olesen, a senior researcher at the Danish Institute of International Studies, said that Greenland and Denmark come out of the deal with the possibility of “ending the crisis without compromising on sovereignty,” while the U.S. obtains a “somewhat more favorable” deal than under the existing defense treaty.

But overall relations between the U.S., Denmark and Greenland "are likely to be haunted by this long after Trump leaves office, and the crisis is likely to have a significant and lasting negative impact on transatlantic relations more generally," he said.

"Rebuilding the lost trust will take decades."

Frederiksen said on Tuesday that she called the agreement a “deal that can last forever,” characterizing it as beneficial to the U.S., Greenland, Denmark and the broader NATO alliance.

"Mr. President, you have been very clear: you don't want adversaries to come too close," she said.

"I fully agree."

Jens-Frederik Nielsen, Greenland’s prime minister, characterised it as “a win-win-win agreement.”

"Your security is synonymous with our security," he said, "and our security is synonymous with yours."