European Union leaders are convening in Brussels on Thursday for an extraordinary summit centered on defence strategy, as French President Emmanuel Macron declared that Europe stands at a "historic crossroads".

Beyond discussions on military build-up, leaders will examine ways to increase support for Ukraine, particularly in light of U.S. President Donald Trump's recent announcement halting American aid to Kyiv. Ukrainian President Volodymyr Zelensky is slated to attend the meeting.

Tensions have escalated across European capitals following the contentious White House encounter between Trump and Zelensky last week. The urgency conveyed in the lead-up to Thursday's summit reflects the seriousness with which EU decision-makers are approaching the matter.

Three years into Russia’s full-scale aggression against Ukraine, the Trump administration's outreach to Russian President Vladimir Putin has sparked concern that Europe can no longer count on its traditional transatlantic ally for security guarantees.

Adding to European unease, Washington on Wednesday froze intelligence-sharing operations with Ukraine, deepening doubts about continued U.S. commitment.

In response, President Macron signaled a new openness to potentially extending France’s nuclear shield to cover EU allies, a remarkable declaration made during a national address on Wednesday evening.

Macron's comments came shortly after Friedrich Merz, the frontrunner to succeed Germany’s Chancellor, suggested new discussions on deeper nuclear cooperation within Europe.

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European Commission President Ursula von der Leyen warned that the continent faces “a level of threat not seen in our lifetimes”. Meanwhile, European Council President António Costa described the summit as “a pivotal point for both Ukraine and Europe’s security architecture”.

In a memo to fellow leaders, von der Leyen stressed that Europe must "rise to the challenge" and mobilize its industrial strength to focus squarely on defence.

Monday saw von der Leyen introduce an ambitious new initiative, ReArm Europe, a sweeping defence stimulus package aimed at drastically increasing military investments with urgency and boldness.

The ReArm Europe framework is designed both to bolster Ukraine and to underline Europe's need to accept greater responsibility for its own defence, acknowledging the declining reliability of U.S. support as a given.

The package encompasses:

• Granting member states more flexibility in their budgets to facilitate higher defence spending

• Making €150bn (£125bn) in defence-related loans available for projects that strengthen EU-wide capabilities—such as missile defence, anti-drone tech, and military logistics—by promoting joint investment and procurement

• Permitting reallocation of EU cohesion policy funds to defence investments

Additionally, the European Investment Bank would be authorized to back military-related initiatives financially.

According to von der Leyen's estimates, this approach could unlock up to €800bn ($860bn; £670bn) in total defence funding across the bloc.

Numerous European leaders have expressed strong endorsement for assertive and prompt movement toward a more secure Europe.

Polish Prime Minister Donald Tusk described the initiative as “a profound transformation”, while Lithuania’s leader Gitanas Nauseda said the coming talks will determine whether the EU is “an action-oriented alliance or merely a debating society”.

Nonetheless, opposition from some pro-Russian leaders within the EU is anticipated.

Earlier in the week, Slovakian Prime Minister Robert Fico criticized the "peace through strength" doctrine as detached from reality.

Meanwhile, Hungarian Prime Minister Viktor Orban urged European Council President Costa to exclude any references to Ukraine in the summit's final outcomes.

Orban—who has consistently opposed EU aid for Kyiv and extolled Trump’s peace messaging—argued that Europe is now experiencing a “strategic schism” with the U.S.

“One faction insists on continuing the conflict in Ukraine, the other seeks resolution,” he said.

Still, Orban expressed willingness for collaboration with fellow leaders on defence and shared security objectives, suggesting avenues for common ground remain.

While the Brussels summit unfolds, UK Defence Secretary John Healey is meeting in Washington with his U.S. counterpart, Pete Hegseth, to discuss the recent freeze in intelligence support for Ukraine.

Their talks are expected to explore the possibilities of a peace initiative and attempt to realign transatlantic cooperation on Ukraine’s long-term defence assurances.

Amid efforts to forge consensus, Macron extended an invitation to Orban for a working dinner Wednesday evening in Paris—immediately after the French president’s solemn address emphasizing the need for European autonomy.

“We must stand strong together in our own defence,” Macron asserted, adding that Europe’s destiny shouldn’t be tethered solely to either Washington or Moscow. “While I hope the U.S. remains beside us, we must prepare for the alternative,” he warned.

Macron also announced that France will host a meeting of EU military chiefs in Paris the following week.

He stressed that Thursday’s talks in Brussels must go beyond rhetoric, aiming to make Europe "more capable of securing itself".

“This moment demands extraordinary actions,” he concluded.