Paris, France - President Joe Biden on Saturday vowed Washington was "standing strong" with Ukraine as French counterpart Emmanuel Macron hosted him on a state visit overshadowed by Kyiv's fight against Russia and the looming US election.

Speaking after visiting Normandy earlier this week to mark 80 years since the D-Day wartime landings, Biden repeatedly emphasized the value of America's European alliances in a swipe at his more isolationist election rival Donald Trump.

With Ukraine struggling to repel Russian advances over two years into the war, Biden insisted that under his rule the US would not flinch in its support for Kyiv.

"Putin is not going to stop at Ukraine," Biden said alongside Macron after talks at the Elysee Palace.

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"All of Europe will be threatened, we are not going to let that happen," Biden said.

"The United States is standing strong with Ukraine. We will not, I say it again, walk away," he added.

Biden (81) is set to face his Republican rival and predecessor Trump later this year in the presidential elections.

Trump has also signaled his lack of interest in international organizations, including the controversial NATO military alliance, and previously boasted he could solve the Ukraine conflict within 24 hours if elected.

Macron (46) emphasized unity with the US under Biden and expressed gratitude for his counterpart's approach to Europe.

"I thank you, Mr. President, for being the president of the world's number one power but doing it with the loyalty of a partner who likes and respects the Europeans," he said.

He said Paris and Washington also shared the same views on Iran, accusing Tehran of pursuing a "strategy of escalation at all levels."

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"Our two countries are determined to exert the necessary pressure to stop this trend," he said.

Biden has been in France since Wednesday and took part in this week's commemorations marking the 80th anniversary of the D-Day landings in northern France involving US, British, Canadian, and other foreign troops that changed the course of World War II.

Also invited to the ceremonies was Ukrainian President Volodymyr Zelensky, who told Biden in a bilateral meeting Friday that Kyiv was counting on "shoulder-to-shoulder" support.

Expressing regret over how an aid package for Ukraine was held up in the US legislature, Biden said: "I wish we could have done it when we wanted to six months earlier, but we got it done."

The US and France have been two of Kyiv's main Western backers since the Russia invasion began in February 2022.

The US leader met Macron for talks at the Elysee Palace, with the two men seen talking one-to-one at a table in the gardens under a sunshade on a warm Paris June afternoon.

"France was our first friend," Biden said, referring to French support in the War of Independence against British colonial rule. "And remains one of our best ones," he added.

The US president and his wife Jill later attended a state banquet at the Elysee given in Biden's honor, with guests including celebrities like the designer and singer Pharrell Williams.

But the stars of the show were American World War II veteran Harold Terens and his 96-year-old bride Jeanne Swerlin, who had married earlier that day in Normandy.

Macron personally congratulated them in his toast to Biden, prompting cheering and a standing ovation.

The week of high-profile events has provided both Biden and Macron with an opportunity to burnish their image with voters.

Macron's camp has faced an uphill struggle to narrow a gap with the far right ahead of European Parliament elections on Sunday.

After his own talks with Zelensky in Paris on Friday evening, Macron said he wanted to "finalize" the creation of a coalition of military instructors to train Ukrainian troops in the coming days.

"We stand at an inflection point in history," Biden said at the state dinner. "It gives me hope to know France and the United States stand together."