US Defense Secretary Pete Hegseth on Thursday announced a comprehensive review to "examine America's force posture and basing in Europe," as Washington presses allies to assume a greater share of the burden for the continent's defence.
"We're doubling down on our effort to make NATO what it always was supposed to be, a balanced alliance with Europe in the lead for its own defence," Hegseth told NATO defence ministers meeting in Brussels.
The review will take up to six months and involve consultations with the US Congress and NATO allies, he said.
While acknowledging that Europe had made progress in boosting defence spending and capabilities, Hegseth said some countries had yet to grasp the "urgency" of the challenge.
He also repeated US criticism of what Washington sees as insufficient support from some allies in the conflict with Iran, calling their initial response "shameful."
The review will also seek to ensure that Washington's "access, basing, and overflight are clearly delineated and assured," Hegseth said.
Hegseth said Washington intends to make its annual financial contributions to NATO contingent on other countries meeting their defence spending targets.
"Where other allies do not spend with urgency, our dues contributions will go down," he said.
"For too long, NATO has been a paper tiger and a one-way street. No more," Hegseth said. "Europe was not supposed to be a dependency of the United States."
The US was aiming to transform "NATO back into a real military alliance that's focused on hard power and real deterrence, a 'NATO 3.0,'" he said.
The announcement comes as European NATO allies race to compensate for cuts announced by the US to certain air and naval assets provided to the alliance in the event of a conflict.
In May, Washington unveiled plans to reduce contributions to NATO's Force Model, an assets planning tool, as part of a broader effort to increase European defence spending and reduce the continent's reliance on the United States.
"I think that's important, friends being honest with friends, making sure that they can step up," Hegseth said of Washington's drive to strengthen Europe's defence capabilities.
Ongoing efforts by allies to backfill the changes were "a good start," he added.
"We can take on what is to be compensated, but not everything right away," German Defence Minister Boris Pistorius said.
Good coordination among allies, including the United States, was now key "to prevent dangerous capability gaps from arising in Europe," he said.
"That the United States of America would do less in Europe to ultimately be able to show more commitment in the Indo-Pacific was always foreseeable," Pistorius said.
He said deep precision strike capabilities were one area where Europe would need more time to fill potential gaps.
"The decision as to who will take over which tasks from the Americans, if and when it comes to that, has not yet been made," Pistorius said.
While some allies are keeping their offers confidential, Belgian Defence Minister Theo Francken pledged additional F-16 fighter jets and surveillance drones.
Merz unfazed by US troop review
German Chancellor Friedrich Merz reacted calmly to Hegseth's announcement.
"We know since the revision of the American national security strategy that the American government has been reviewing its troop presence worldwide," Merz said, referring to a White House document published last November.
"This also applies to Europe, and it also applies to Germany," he said.
"That is why we have always said that we must strengthen Europe's defence capabilities. We are making a major effort to strengthen ourselves."
According to the US Defense Manpower Data Center, Germany hosts more than 37,000 active-duty US troops. President Donald Trump said in May that the United States would withdraw around 5,000 military personnel from Germany.
At a NATO summit last year, allies agreed to invest at least 3.5% of GDP in core defence spending, with a further 1.5% earmarked for defence-related areas such as infrastructure. The combined 5% target is to be reached by 2035. The previous benchmark had been 2%.
Rutte seeks to reassure allies
NATO Secretary General Mark Rutte sought to downplay concerns that the US cuts, which took effect immediately, could undermine the alliance's ability to defend Europe.
"We are really in a good place," he said. "The Europeans are now backfilling it. Some of this is already done, some of this is in the progress. We are working on that."
"If war breaks out, clearly what all allies will do, including the United States, is max out whatever they can do," Rutte said.
"I have every confidence that we will fight that war, and we will win it," he said.
Rutte has previously said NATO's nuclear umbrella was unaffected by the changes.
"The strategic nuclear forces of the Alliance remain the supreme guarantee of Allied security and underpin NATO's extended deterrence architecture," a statement issued by NATO's Nuclear Planning Group said on Thursday.
Participating countries "agreed to continue enhancing NATO's nuclear deterrence mission by modernizing NATO's nuclear capabilities, strengthening its nuclear planning capacity, and adapting to achieve its security interests."
"The Alliance maintains a safe, secure, effective, and credible nuclear posture to preserve peace, prevent coercion and deter aggression," the statement said.
