Denmark has unveiled one of its most ambitious military expansions in modern history, committing $4.2 billion to strengthen Arctic and North Atlantic security – in a clear alignment with President Donald Trump's renewed defense agenda.

Denmark's new Second Agreement on the Arctic and North Atlantic forms part of the 2024–2033 Defense Agreement and includes a broad range of measures to modernize Denmark's military presence in the "High North," including Greenland.

Copenhagen's decision in favor of an Arctic buildup comes after Trump said earlier this year that Greenland, a territory of Denmark, was "necessary ... for international security."

"You have Russian boats all over the place, you have China's boats all over the place — warships — and they [Greenland] can't maintain it," Trump said.

Denmark's multibillion-plan will fund new Arctic naval vessels, a maritime patrol aircraft capacity, an air-surveillance radar system, additional drones, and a new Joint Arctic Command headquarters in Nuuk, Greenland.

The plan also includes infrastructure upgrades and a North Atlantic undersea cable connecting Denmark, Greenland, and the Faroe Islands.

Danish officials described the move as a "historic step" that reinforces NATO's northern defenses and deepens Denmark's cooperation with the United States and its allies.

According to sources familiar with the discussions, the total investment amounts to 27.4 billion Danish kroner — roughly $4.2 billion — and represents a major escalation of Denmark's Arctic commitments.

Defense Minister Troels Lund Poulsen said Denmark "significantly strengthens the capabilities of the Danish Armed Forces" with its enhanced military posture for Greenland and the Arctic.

The agreement was developed in close partnership with the governments of Greenland and the Faroe Islands, both of which play critical roles in monitoring the North Atlantic.

The package adds two new Arctic vessels with icebreaking capacity, expanding the Danish Arctic fleet to five.

It also introduces a new special operations Arctic unit, designed for rapid deployment and first-response missions, as well as a drone-training module and a planned Greenlandic Rangers corps to be completed by 2026.

The initiatives aim to enhance Denmark's ability to assert sovereignty, respond to emergencies, and provide operational support for NATO and allied forces.

Sources indicate that the maritime patrol aircraft component will be developed in collaboration with a NATO ally and will include anti-submarine capabilities, a move seen as particularly important amid increased Russian submarine activity in the Arctic and North Atlantic.

The agreement also includes funding for a new radar installation in East Greenland, significantly improving early warning and surveillance coverage across the strategic GIUK Gap — the naval corridor between Greenland, Iceland, and the United Kingdom that has reemerged as a focal point of Western defense strategy.

Danish officials privately acknowledge that these measures reflect not only national security priorities but also a political signal to Washington.

According to senior defense sources, Denmark's government views the expansion as a "demonstration of reliability" toward Trump's call for European nations to take greater responsibility within NATO.

The announcement comes alongside another major development — Denmark's decision to purchase 16 additional F-35 fighter jets, expanding its total fleet from 27 to 43 of the advanced aircraft.

Defense Minister Poulsen described the deal as a "historic strengthening of the Danish Air Force," calling it a cornerstone of the nation's future defense posture.

The procurement, valued in the billions, includes spare parts, flight simulators, deployment kits, and new training infrastructure. The first aircraft are expected to arrive within the next year, with full operational readiness by 2027.

According to sources within NATO command, the Danish F-35 expansion was widely viewed as a "clear response" to Trump's emphasis on transatlantic military readiness and interoperability.

The United States, as lead manufacturer of the F-35, has been pressing its European partners to standardize air capabilities and increase spending.

Officials also note that Denmark's participation in NATO's joint air-to-air refueling program and its offer to establish a NATO Special Operations Headquarters in the Arctic align closely with Trump's push for a stronger, more self-reliant European pillar within the alliance.

"The president's message that Europe must invest in its own security is being heard in Copenhagen," said one senior European diplomat, adding that "Denmark is now one of NATO's most proactive contributors relative to its size."

Defense sources say the projects together will bring Denmark's total defense spending on track with NATO's 5% GDP target — a benchmark Trump has made central to his policy of renewed transatlantic accountability.

According to Danish and U.S. officials familiar with the negotiations, the Arctic and F-35 agreements were coordinated with American defense advisers in recent months, with Washington reportedly encouraging the fast-tracking of certain elements.

"Denmark has proven itself as one of our most dependable allies," one U.S. defense source said. "Their investments in the Arctic directly strengthen NATO's northern flank and support the president's strategy to keep Europe capable and committed."