The meeting in Paris will be a chance for participants to “reaffirm their unity as well as their determination to defeat the war of aggression waged by Russia in Ukraine”, the French presidency said.

It also signals Macron’s eagerness to present himself as a European champion of Ukraine’s cause, amid growing fears that American support could wane in the coming years.

“Battered and bruised, but still standing. Ukraine is fighting for itself, for its ideals, for our Europe. Our commitment at its side will not waver,” Macron tweeted, to mark two years since the conflict broke out.

For Macron, the conference is also a chance to show European autonomy in security matters, which he called for even before the invasion.

German Chancellor Olaf Scholz and Polish President Andrzej Duda will be among some 20 European heads of state and government present at the conference, which will be opened by a video address from Ukrainian President Volodymyr Zelensky.

Other states will be represented at ministerial level, with Foreign Secretary David Cameron travelling to Paris for the UK. The United States and Canada will also be represented.

According to the French presidency, the meeting will “examine all means to support Ukraine effectively”.

Western officials acknowledge that Russia risks gaining the upper hand in the conflict in 2024 as Ukraine runs out of weapons and ammunition.

Ukrainian Defence Minister Rustem Umerov said on Sunday that half of Western military aid pledged to Kyiv is delivered late, lamenting that “commitment does not constitute delivery”.

Revealing the magnitude of Ukraine’s human losses, Zelensky said 31,000 Ukrainian soldiers had been killed in the war with Russia.

A French presidential official, who asked not to be named, said the meeting needed to contradict any “impression that things are falling apart” after Ukraine’s setbacks on the battlefield.

“We want to send a clear message to Putin that he will not prevail in Ukraine,” said the official.

Even if new aid announcements are not planned, participants will examine ways to “do things better and more decisively,” the official added.

There are growing doubts about the viability of long-term American backing for Ukraine as a new aid package struggles to find legislative approval and Donald Trump eyes a return to the presidency in elections later this year.

Zelensky said on Sunday that his country’s victory “depends” on Western support and that he was “sure” the United States would approve a critical package of military aid.

“We are neither resigned nor defeatist,” said the French official, adding, “there will be no victory for Russia in Ukraine.”

Debra Cagan, a former American diplomat and now senior advisor at the Atlantic Council’s Eurasia Center, said if the West had given Ukraine weapons such as F-16 combat aircraft or Taurus German missiles “we would be seeing an entirely different conflict now”.

“And that is what indecisiveness does, it causes more deaths, more destruction and harder decisions down the road,” she added.

The conference is due to start at 5pm with a news conference expected from Macron around 9.30pm.