The United States, Denmark, and Greenland have signed a landmark security agreement on the sidelines of the United Nations General Assembly in New York, formalising an expanded American role in the defence of the Arctic island. The deal, signed by US President Donald Trump, Danish Prime Minister Mette Frederiksen, and Greenland's Prime Minister Jens-Frederik Nielsen, grants Washington permanent access rights, the authority to construct new military bases, and a veto over any attempts by adversarial nations to establish a military presence or make sensitive investments on the island. US Secretary of State Marco Rubio described the agreement as addressing American national security concerns "permanently and fully."

Greenland, a vast Arctic island roughly three times the size of Texas, is an autonomous territory within the Kingdom of Denmark. It holds immense strategic value due to its position between North America and Europe, its untapped critical mineral reserves, and its proximity to increasingly contested Arctic shipping routes. The deal reportedly builds on a 1951 defence pact that already allowed the US to operate military bases there, but adds significant new provisions: notably, that neither China nor Russia may establish bases or undertake sensitive investments without written American consent. Three sources familiar with the agreement indicated that the US plans to reopen a former Cold War-era military base at Narsarsuaq in southern Greenland, and to establish a presence at Mestersvig, a remote outpost currently used by Denmark's elite Sirius Dog Sled Patrol special forces unit.

Frederiksen emphasised that the agreement recognises Danish sovereignty and the Greenlandic people's right to self-determination, calling it "a good agreement from a Danish point of view." She also framed it in collective terms, arguing that enhanced Arctic security benefits Nordic countries, NATO, and Europe as a whole. Greenland's Prime Minister Nielsen said simply, "It is for the benefit of us all." NATO's spokesperson welcomed the deal, saying it would "help strengthen security, stability, and cooperation in this vital region."

The agreement comes after months of intense diplomatic pressure from Trump, who since returning to the White House in January 2025 had repeatedly insisted the US needed control of Greenland and at times declined to rule out military or economic coercion to achieve it. Those statements triggered a sharp diplomatic crisis within NATO. Behind-the-scenes negotiations ultimately produced a compromise that, while far short of the outright annexation Trump had previously floated, is being presented by his administration as a decisive American victory. The deal's full text has not been made public.

The signing carries broader significance for the transatlantic alliance at a moment of strained trust. It coincided with the completion of NATO's weeklong Arctic Shield military exercises and the passage by the US Congress of a Russia sanctions bill. Earlier this month, the European Union also signed a €200 million investment plan with Danish and Greenlandic representatives, a move some analysts interpret as a parallel effort to strengthen European influence over the island's economic future. For Greenland's approximately 56,000 inhabitants, the convergence of American military investment, US business interest in mineral ventures, and European economic engagement signals a period of significant, and potentially transformative, outside attention.