President Joe Biden met with Ukrainian President Volodymyr Zelenskyy in Paris on Friday as the United States clashes with Kyiv and the Kremlin over supplies of American weapons.

Biden offered a first public apology for the monthslong delay in U.S. military aid that Russia has exploited to make crucial battlefield advances. He also announced a new package of $225 million in weapons, including air defense interceptors, artillery ammunition and other critical capabilities.

“I assure you the United States will stand with you,” Biden told Zelenskyy. “We are still in, completely,” he added.

The meeting in the French capital comes as Kyiv’s military is under pressure from a new Russian offensive in the north and intense attacks in the east, a perilous moment that saw its allies let Ukraine conduct some strikes inside Russia using Western weapons.

It also follows the D-Day 80th anniversary events in Normandy, which Zelenskyy attended and where Biden drew parallels between that pivotal battle to free Europe from Nazi domination and Ukraine’s current fight against Russia.

Biden and Zelenzkyy met at the White House in December, when the Ukrainian leader came to lobby Congress to approve new military aid for his struggling troops on the front lines. But Kyiv has grown frustrated by the pace of military assistance and continued limits on its use of the weapons once received.

French President Emmanuel Macron, who is hosting the two leaders, gave Kyiv his own boost Thursday.

France will provide its Mirage combat aircraft and train a brigade of Ukrainian soldiers, he announced, though details were not immediately clear.

Tensions between Kyiv’s allies and Moscow are at an all-time high after the decision to allow Ukraine limited use of Western-supplied weapons to strike military targets inside Russian border regions.

Despite this shift, Kyiv’s troops remain outnumbered and outgunned, and Zelenskyy is pushing for more.

He has already said that the limited loosening of restrictions is not enough, with Ukraine thought to be eager to use other long-range Western weapons to hit deeper inside enemy territory.

The new support for Ukraine has infuriated the Kremlin, however. Russian President Vladimir Putin warned Wednesday he could deploy arms to countries that could strike the West in response, and said Washington and its partners were wrong to assume he would never use nuclear weapons.

Putin is scheduled to speak at the St. Petersburg International Economic Forum later Friday, where he is likely to touch on the same topics.

His troops have been bogged down in the Kharkiv border region after they launched a new assault last month, stretching the limited resources of Ukraine’s army even further. Despite Russia claiming a number of villages in the first weeks of the offensive, it appears Kyiv has been successful at stalling the advance.

Zelenskyy told Biden on Friday that U.S. decisions have had “a very positive influence” in the region.

Biden signaled in an interview Thursday that Washington remains cautious, emphasizing that Kyiv still can’t use American weapons to strike deep into Russia to, for example, target Moscow or the Kremlin itself.

But he nonetheless offered his rhetorical backing to Kyiv’s cause, drawing a direct connection with the Allied fight against Adolf Hitler.

Speaking at the D-Day ceremony at the Normandy American Cemetery earlier Thursday, Biden called Putin “a tyrant bent on domination.”

“We will not walk away,” he said, speaking of U.S. support for Europe’s present struggle in front of World War II veterans. “Because if we do, Ukraine will be subjugated.”

Biden will deliver another speech Friday, echoing former President Ronald Reagan with an address on democracy and freedom at Pointe du Hoc — the Normandy cliffs that separate the beaches where American troops landed on D-Day.

Biden was not the only American to draw the parallels between Ukraine’s fight and World War II.

Zelenskyy shared a touching moment with a U.S. veteran Thursday, with the two embracing and exchanging words of gratitude.

“You are the savior of the people,” the veteran said. Zelenskyy responded: “No, you saved Europe.”

This article was originally published on NBCNews.com