The US House of Representatives has approved sending $60.8bn (£49bn) in foreign aid to Ukraine.
Democrats and Republicans joined together after months of deadlock over renewed American support to help Ukraine fend off Russia’s invasion.
Representatives could be seen waving small Ukrainian flags as it became clear the package was going to pass.
Ukrainian President Volodymyr Zelenskyy tweeted to say he was “grateful” for the decision, which he said “keeps history on the right track”.
He said: “Democracy and freedom will always have global significance and will never fail as long as America helps to protect it.
“The vital US aid bill passed today by the House will keep the war from expanding, save thousands and thousands of lives, and help both of our nations to become stronger.”
Representatives also approved bills to send foreign aid to Israel, give security assistance to Taiwan and allies in the Indo-Pacific, and a measure containing several foreign policy proposals including a threat to ban Chinese-owned social media app TikTok.
The package will now go to the US Senate, where it is likely to be passed on Tuesday. Mr Biden has then promised to sign it immediately.
The Kremlin said the passage of the bill would “further ruin” Ukraine and result in more deaths.
Spokesman Dmitry Peskov told the TASS news agency a provision allowing Washington to confiscate seized Russian assets and transfer them to Ukraine for reconstruction would tarnish the image of the US.
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UK Foreign Secretary Lord Cameron said the funding was “a vital step forward”.
“If Putin ever doubted the West’s resolve to back Ukraine, this shows our collective will is undimmed,” he tweeted.
“With support, Ukraine can and will win.”
But Donald Trump ally Marjorie Taylor Greene, a Republican representative who has opposed helping Ukraine in its war against Russia, said “people have been too obsessed with voting for foreign wars and the war industry”.
Speaking after the vote passed, she said: “This is the sellout of America today. When we had members of Congress in there waving the Ukrainian flag on the United States House of Representatives floor, while we’re doing nothing to secure our border, I think every American is going to be furious.”
US President Joe Biden first requested the funding in October, as Ukraine’s military supplies began to dwindle.
In February, Mr Zelenskyy urged Congress to pass the funding, saying if it did not “it will leave me wondering what world we are living in”.
