The Pentagon has launched a comprehensive review of US military force posture in Europe aimed at accelerating NATO allies' assumption of primary responsibility for the continent's conventional defence, Under Secretary of Defence Elbridge Colby said.

Colby said on Monday the Europe Posture Review follows an announcement by Defence Secretary Pete Hegseth at the recent NATO defence ministers' meeting in Brussels and is intended to reassess the US military presence on the continent.

"As the Secretary laid out then, this will be a real review, designed to ensure that NATO is moving fast and irreversibly toward Europe taking primary responsibility for its conventional defence," he said on X.

Colby said the review is expected to accelerate NATO's transition toward a "stronger, more equitable and sustainable" alliance, building on policies pursued under US President Donald Trump to encourage European allies to assume a larger share of the defence burden.

"In doing so, the Review will further the goal of fully restoring NATO’s character as a powerful warfighting organisation – a NATO 3.0. This will put NATO on the track for lasting, sustained success, especially as we confront simultaneous challenges across theatres," he added.

'One-way street' NATO

The review will assess US force posture in Europe to ensure that it aligns with the administration's 2025 National Security Strategy and 2026 National Defence Strategy, Colby said, adding that officials will develop a range of options based on strategic analysis and current geopolitical and military conditions.

"I look forward to working closely with General Alexus Grynkewich, the Supreme Allied Commander Europe, on this critical effort," he said.

"We also look forward to further extensive consultations on this key initiative with our allies in Europe, Congress, and other parts of the US Government."

In his comments, Colby cited Pentagon Chief Pete Hegseth's remarks in last month's NATO Defence Ministerial in Brussels, during which he said US allies "must step up."

"President Trump has been very clear on this point for many years, and over two administrations, and for too long, NATO has been a paper tiger and a one-way street. No more, and that's what the Hague Summit is all about," Hegseth said then.