WASHINGTON, Sep 21 (Aljazeera) - Ukrainian President Volodymyr Zelenskyy has made his second visit to Washington, DC, since Russian forces launched a full-scale invasion of his country.

But unlike in his first trip to the United States Capitol, Zelenskyy faced a congress less inclined to back the war effort with large aid packages, despite pledges from top Democrats to “stand behind” Ukraine.

In brief public remarks before the White House Cabinet on Thursday, Zelenksyy struck a note of gratitude, calling his negotiations in Washington “productive” and “strong”.

“Thank you for all these 575 days,” he said, referencing the length of time since Russia invaded in February 2022. “Thanks to the American people, all these days they are together with us, with Ukrainians, with ordinary people, all of us.”

He also highlighted new military assistance, worth $128m, announced by US President Joe Biden on Thursday.

“It has exactly what our soldiers need now,” he said, calling it a “very powerful package”.

Biden, a Democrat, used his presidential “drawdown authority” to authorise the aid, as further funds for Ukraine prove to be a sticking point in the US Congress.

“Today, I approved the next tranche of US security assistance to Ukraine, including more artillery, more ammunition, more anti-tank weapons,” he said. “And next week, the first US Abrams tanks will be delivered to Ukraine.”

The Cabinet meeting culminates a whirlwind charm offensive from the Ukrainian president, who travelled to New York earlier this week to rally support among world leaders at the United Nations.

But as Zelenskyy faced US lawmakers on Thursday, the stakes were particularly high.

Since the full-scale Russian invasion began in 2022, the US has committed more money than any single country to aid Ukraine, with much of that support taking the form of military assistance.

The US Congress itself has approved aid amounting to over $113bn. But the last time Congress voted on an aid package was in December — and control of the House of Representatives has since switched hands, from Democrats to Republicans.

Nevertheless, Biden has called on Congress to approve an additional $24bn for Ukraine aid, a request that Republicans, particularly on the far right, have baulked at.

Some have called instead to slash funding for Ukraine, in favour of domestic priorities and limited government spending.