Ukraine's Volodymyr Zelensky thanked jubilant US lawmakers during a defiant visit to the wartime capital on Wednesday for funding the war, remarking that it was ‘not charity’, rather an ‘investment’ in global security and democracy.

The whirlwind stop in Washington, his first visit outside the country since Russia invaded in February, comes at a time when there are fears that allies are fed up with costly wars and disruptions to the world's food and energy supplies. It was meant to revive support for his country around the world.

Zelenskyy called the tens of billions of dollars in U.S. military and economic assistance provided over the past year vital to Ukraine`s efforts to beat back Russia and appealed for even more in the future. And Congress planned to vote this week on a fresh spending package that includes about $45 billion in additional emergency assistance to Ukraine.

The speech to Congress came after President Joe Biden hosted Zelenskyy in the Oval Office for strategy consultations, saying the U.S. and Ukraine would maintain their “united defence” as Russia wages a “brutal assault on Ukraine`s right to exist as a nation.” Biden pledged to help bring about a “just peace.”

The visit had been long sought by both sides, but the right conditions only came together in the last 10 days, U.S. officials said, after high-level discussions about the security both of Zelenskyy and of his people while he was outside of Ukraine. Zelenskyy spent less than 10 hours in Washington before beginning the journey back to Ukraine.

Zelenskyy received thunderous applause from members of Congress and presented lawmakers with a Ukrainian flag autographed by front-line troops in Bakhmut, in Ukraine`s contested Donetsk province. Pelosi, in turn, presented Zelenskyy with an American flag that had flown over the Capitol that day, and Zelenskyy pumped it up and down as he exited the chamber.

He rejected Biden`s framing of finding a “just peace,” saying, “For me as a president, `just peace` is no compromises.” He said the war would end once Ukraine`s sovereignty, freedom and territorial integrity were restored, and Russia had paid back Ukraine for all the damage inflicted by its forces. Biden, for his part, said Russia was “trying to use winter as a weapon, but Ukrainian people continue to inspire the world.” During the news conference, he said Russian President Vladimir Putin had “no intention of stopping this cruel war.”

The two leaders appeared to share a warm rapport, laughing at each other`s comments and patting each other on the back throughout the visit, though Zelenskyy made clear he will continue to press Biden and other Western leaders for ever more support. He said that after the Patriot system was up and running, “we will send another signal to President Biden that we would like to get more Patriots.”

“We are in the war,” Zelenskyy added with a smile, as Biden chuckled at the direct request. Biden told Zelenskyy that it was “important for the American people, and for the world, to hear directly from you, Mr President, about Ukraine`s fight, and the need to continue to stand together through 2023.”

Zelenskyy had headed to Washington after making a daring and dangerous trip Tuesday to what he called the hottest spot on the 1,300-kilometer (800-mile) front line of the war, the city of Bakhmut. Poland`s private broadcaster, TVN24, said Zelenskyy crossed into Poland early Wednesday on his way to Washington.

U.S. and Ukrainian officials have made clear they do not envision an imminent resolution to the war and are preparing for fighting to continue for some time. Biden repeated that while the U.S. will arm and train Ukraine, American forces will not be directly engaged in the war. The latest U.S. military aid package includes not only a Patriot missile battery but precision-guided bombs for fighter jets, U.S. officials said.

“It`s a defensive system,” Biden said of sending the missile system. “It`s not escalators — it`s defensive.” GOP leader Kevin McCarthy of California has said his party will not write a “blank check” for Ukraine.

Senate Majority Leader Chuck Schumer opened the chamber’s session on Wednesday by saying that passage of the aid package and confirmation of the new U.S. ambassador to Russia, Lynne M. Tracy, would send a strong signal that Americans stand “unequivocally” with Ukraine. Tracy was confirmed later on a 93-2 vote.

The Senate’s top Republican, Kentucky Sen. Mitch McConnell, said “the most basic reasons for continuing to help Ukraine degrade and defeat the Russian invaders are cold, hard, practical American interests.” He said “defeating Russia’s aggression will help prevent further security crises in Europe.”

Russia has attacked Ukraine's power equipment, hoping to leave people without electricity as freezing weather sets in. With the fighting in the east at a stalemate, Moscow has used missiles and drones to attack Ukraine's infrastructure.