Joe Biden, the U.S. president, apologized publicly to Ukraine on Friday for the months-long holdup by Congress in American military aid that allowed Russia to gain on the battlefield.

Biden apologized after meeting with Ukrainian President Volodymyr Zelenskyy in Paris, who called for bipartisan U.S. backing going forward “like during World War II.”

The two men had met a day before at the celebrations marking the 80th anniversary D-Day landings. Biden had made a connection between the allied forces who helped liberate Europe from Nazi Germany, and the current effort to defend Ukraine against Russia’s invaders. Zelenskyy was given rapt applause.

“I apologize for the weeks where I didn’t know what was going to happen regarding funding,” Biden said. He was referring to conservative Republicans who held up a $61 billion package of military aid for Ukraine for six months. The Democratic President insisted, however, that the American public would stand by Ukraine over the long term. “We’re still in. Completely. “He said, “completely.”

The apology, and Zelenskyy’s call for rock-solid US support similar to the allies in WWII, served as a stark reminder that despite Biden’s claims of a unwavering commitment by the United States to Ukraine recalcitrance in Congress and isolationism in American politics has exposed its fragility. The specter Donald Trump’s presidential candidacy also loomed large over the discussion. Although it was not mentioned, Trump, the Republican candidate and former president, has been praised by Russian President Vladimir Putin, and has sparked Ukrainian fears that he will call for Ukraine to cede territories to end the war.

Zelenskyy called on all Americans to help defend his country against Russia’s invasion. He thanked the lawmakers who finally came together to approve a weapons package that allowed Ukraine to stop Russian advances over recent weeks.

Zelenskyy stated, “It is very important for all Americans to remain united with Ukraine in this unity of the United States of America as they were during World War II.” How the United States saved human lives and saved Europe. We count on you to continue standing shoulder-to-shoulder with us.

Ukraine is trying its best to repel a Russian offensive that has been intensifying in the eastern parts of the country. The United States, by far, is Kyiv’s largest wartime supporter. The Russian offensive is aimed at the Ukrainian border areas of Kharkiv, Donetsk and other eastern regions. However, Ukrainian officials believe it could expand as Russia’s larger army tries to show its superiority.

The offensive aims to take advantage of Kyiv’s shortages in ammunition and troops along a 1,000-kilometer frontline (620 miles).

Zelenskyy has been frustrated by the slow delivery of Western weapons pledged, and Biden has also been frustrated by his hesitation to supply more hardware out of fear of upsetting Russian President Vladimir Putin. This has led to tensions in their relationship.

Biden announced on Friday that the U.S. would send $225 million worth of military aid to Ukraine. U.S. officials announced Thursday that the latest package included munitions for HIMARS (High Mobility Artillery Rocket System), as well as mortars and a variety of artillery shells.

Biden referred to the additional aid he received in his meeting Zelenskyy in Ukraine as “money to rebuild the electric grid”. This was a reference, according to aides, to the additional air defense and anti-missile defense systems included in the new package.

Some NATO allies, including the U.S., eased their stance last week amid Russia’s latest onslaught. With Ukraine’s army in ruins and its military in a state of chaos due to Russia’s recent assaults, they said they would permit Ukraine to use weapons that they delivered to Kyiv for limited attacks within Russia.

This prompted a furious reaction from the Kremlin which warned that Europe’s largest conflict since World War II might spiral out of control.

Biden and Zelenskyy were present at the D-Day anniversary celebrations in Normandy in northern France on Thursday. They attended with other European leaders who had supported Kyiv in its war efforts. Biden said “we won’t walk away” from Ukraine. He drew a parallel between the war to free Europe from Nazi dominance and today’s fight against Russian aggression.

Ukraine portrays its struggle against the Kremlin as a conflict between Western democracy and Russian tyranny. Russia claims it is protecting itself from a NATO expansion to the east.

Zelenskyy, in a 20 minute speech at the National Assembly (the lower house of France’s parliament), drew parallels between the sacrifices that were made during World War II, and the current struggle his country is fighting.

Zelenskyy stated that “this battle is at a crossroads.” “This is a moment when we can write history in the way that we want to. Or we can be victims of the history that suits… our enemy.”

Zelenskyy’s Ukrainian speech was interrupted frequently by applause from the lawmakers. The French speaker received a standing applause when he addressed the crowd in French, “Dear France: I thank you for standing beside us as we defend our lives.”

Emmanuel Macron announced Thursday night that France would provide its Mirage combat plane to Ukraine.

Macron is a vocal proponent of Ukraine. He said that the possibility of Western troops being on the ground in Ukraine was not “ruled out” in February.

Zelenskyy started his day of meetings with a welcome ceremony in Paris at the monument Invalides, which is home to Napoleon’s tomb.

Zelenskyy had a visit scheduled for the next day to the Nexter arm manufacturer in Versailles. Nexter manufactures the Caesar self propelled howitzers, among other weapons that France has provided to Kyiv.

Macron was to also meet him at the Elysee Palace.

Zelenskyy’s trips abroad aim to bring Ukraine’s situation into the spotlight, gain more military support for its battle against Russia’s invasion and secure long-term Western assistance through bilateral alliances.

In February, France and Ukraine signed a bilateral security agreement for ten years. Zelenskyy signed bilateral agreements similar to those with other European countries.