The United States, Denmark, and Greenland have signed a landmark trilateral security agreement that permits Washington to build two new military bases on Greenland and significantly expand its existing Arctic footprint. The deal was signed on the sidelines of the United Nations General Assembly in New York by US President Donald Trump, Danish Prime Minister Mette Frederiksen, and Greenland's Prime Minister Jens-Frederik Nielsen — apparently bringing to a close more than a year of acute diplomatic tension within NATO.
Under the agreement, which amends and updates a 1951 defence treaty between the US and Denmark, Washington will be allowed to establish new bases at Narsarsuaq — a former Cold War airfield with deep-water access in Greenland's south — and at Mestersvig, a remote eastern outpost currently used by the Sirius Dog Sled Patrol, a Danish special forces unit. The US will also be permitted to "modernise and expand" its existing Pituffik Space Base in northwestern Greenland, where more than 100 American military personnel are permanently stationed. The technical details and modalities of the new bases must still be mutually agreed by all parties, meaning neither Denmark nor Greenland has surrendered its approval rights. The deal has no end date and grants US aircraft and naval vessels broad access across Greenland and its territorial waters. Non-NATO states are explicitly barred from establishing military installations on the island, and foreign investment from outside NATO or the European Union is restricted in sensitive sectors such as critical infrastructure and resource extraction.
Crucially, the agreement reaffirms Danish "sovereignty and territorial integrity" over Greenland and recognises the Greenlandic people's right to self-determination under international law. It even provides for the scenario of future Greenlandic independence, stipulating that an independent Greenland would need to remain in NATO and honour existing arrangements. Greenland is a semi-autonomous territory of the Kingdom of Denmark — a vast Arctic island three times the size of Texas with a population of roughly 57,000 — that holds significant strategic value due to its position on the shortest route between Europe and North America, as well as its substantial reserves of rare earth minerals and energy resources.
The mood at the signing ceremony was notably warm. Trump hailed it as "an unprecedented agreement" that would "protect Europe in addition to America," while Frederiksen called it "a milestone" that could "last forever" and stressed it respected Greenland's sovereignty. Nielsen described it as a "win-win-win" and said it was an agreement made "with us, not just about us." NATO Secretary-General Mark Rutte welcomed the deal as one that "enhances our collective security," and German Chancellor Friedrich Merz called it "good news for the security of Greenland."
The deal represents a significant de-escalation from the crisis that erupted in January 2025, when Trump — who had first floated the idea of purchasing Greenland during his first term — refused to rule out military or economic force to acquire the territory, a threat that drew a rare joint rebuke from European leaders and shook the NATO alliance. While Trump did not achieve the outright annexation he had publicly demanded, the agreement delivers the first major expansion of US military infrastructure in Greenland since the Cold War, when Washington maintained 17 installations and more than 10,000 personnel on the island. Both Denmark's and Greenland's parliaments must still ratify the pact before it takes full effect.