Defense Secretary Pete Hegseth speaks to reporters upon arrival at NATO headquarters in Brussels for meetings with the alliance's defense ministers on Feb. 13, 2025. (X/U.S. Mission to NATO)

Defense Secretary Pete Hegseth hammered home a message upon arrival at NATO headquarters Thursday that allies need to show more urgency in building up their respective militaries to counter a more aggressive Russia.

“The war in Ukraine, the aggression by Russia has been a factory reset for NATO, a realization that this alliance needs to be robust and strong and real,” Hegseth said as high-level talks got started in Brussels.

Across-the-board defense spending increases are needed, given “an urgent, real threat to the Continent,” he said.

Hegseth’s comments came one day after he delivered a jolt to allies when he laid out parameters for anticipated peace talks that President Donald Trump is expected to convene.

On Wednesday, Hegseth said any return to Ukraine’s prewar borders is unrealistic, as is NATO membership for Kyiv. He also said an international peacekeeping force, minus the United States, could play a role in ensuring that fighting doesn’t restart.

Such a force would function without NATO’s collective security guarantee, he said.

Hegseth’s statements that laid out conditions for formal talks amounted to a repudiation of the long-standing NATO mantra of being in it for the “long haul” with Ukraine, and that there would never be “discussions about Ukraine without Ukraine.”

The idea of demanding that Ukraine give up large swaths of its territory as part of any peace has rattled some allies, especially on NATO’s eastern flank. Russia has occupied Ukrainian land roughly equal in total size to the state of Pennsylvania.

Hegseth on Wednesday was asked whether the new dynamic being pushed by the White House should be interpreted as a betrayal of Ukraine.

“There is no betrayal there,” Hegseth said. “There is a recognition that the whole world and the United States is invested and interested in peace, a negotiated peace. As President Trump has said, stopping the killing.”

Any agreement between the two countries “will require both sides recognizing things they don’t want to,” he said.

Hegseth also has delivered a blunt message to NATO allies, saying that European militaries will be expected to carry most of the security burden on the Continent given U.S. commitments elsewhere.

While the U.S. will remain “an active part of this alliance,” NATO countries will need to spend significantly more to fill the defense gaps, he said.

Trump has called on members to increase minimum spending levels from the current benchmark of 2% of gross domestic product to 5%.

A key question that remains unanswered is how soon allies are expected to field ground forces capable of deterring potential Russian aggression without a major contribution from the U.S. military.

Earlier this week, Hegseth said it was too soon to say whether troops in Europe would be withdrawn. But the expectation is that a larger U.S. focus in the Pacific will eventually have implications for the American military mission in Europe.

Secretary-General Mark Rutte said Thursday that the situation means allies need to ramp up fast.

Russia, which has shifted to a wartime economy, is churning out more ammunition in three months than all of NATO’s European members do in a year, he said.

And a new report issued Wednesday by the International Institute for Strategic Studies said Russian military spending outpaces all of Europe put together when Russia’s lower production costs are factored in.

The IISS analysis found that Russia’s total military expenditure grew by 42% in 2024 to an estimated $145.9 billion, compared with Europe’s collective $457 billion.

However, when purchasing power parity was taken into consideration, Russia’s total adds up to the equivalent of $462 billion, IISS said.

Rutte has warned that if allied spending remains at current levels, security on the Continent will be put in danger given the scale of Russia’s military investments.

“We need to ramp up defense spending because it is clear that the U.S. rightly requires us to do more here on the European side and the Canadian side of NATO,” Rutte said Thursday.

This story will be updated.