Biden signed the Lend-lease Act in the Oval Office, saying the United States supports Ukrainians' "fight to defend their country and their democracy against (Russian President Vladimir) Putin's brutal war."

He also signaled that he is ready to make a political concession in Congress so that he can win rapid approval of a request for another $33 billion in funds for supporting Ukraine.

Biden had previously demanded that approval be coupled with support for funding unrelated government anti-Covid programs. But because Republicans are dragging their heels on Covid-related expenses, Biden said he is ready to drop the Covid funding demands for now and just get the Ukraine money through.

"We cannot afford delay in this vital war effort," he said in a statement, urging that Congress get the Ukraine funding bill "to my desk right away."

The updating of the historic Lend-lease measure was especially resonant coming hours after Putin oversaw a military parade on Red Square in Moscow for the annual commemoration of the Soviet victory against Nazi Germany. Putin has turned the event into a spectacle justifying his war on pro-Western Ukraine, which he falsely claims is occupied by Nazis.

Back in the 1940s, the United States and the communist Soviet Union were briefly allies against their common German enemy. It was then that President Franklin Roosevelt first used the Lend-lease measure, removing bureaucratic obstacles to funnel billions of dollars of equipment to European partners, including to the Soviets.

Today, Lend-lease is being used to open the spigots on artillery, anti-aircraft missiles, anti-tank weapons and other powerful Western weapons used by Ukraine's military against Russian forces.

Biden emphasized the symbolism of the date, noting he was signing the act the day after the United States and Western Europe marked their separate Victory in Europe day May 8th.

He also underlined that Monday itself marked the anniversary of the May 9 Europe Day, which celebrates the founding of the European Union in 1950 and creation of an "economic powerhouse" and "global force for peace."

Acknowledging the billions of dollars already spent by the United States, Biden said "caving to aggression is even more costly."

In a tweet, Ukrainian President Volodymyr Zelensky welcomed the measure, also harking back to the war against Germany.

"Today's signing of the law on Lend-lease is a historic step. I am convinced that we will win together again. And we will defend democracy in Ukraine. And in Europe. Like 77 years ago," Zelensky wrote.