In Congress, Republican and Democratic leaders are entrenched in a spending battle that could spark a US government shutdown, with a $24 billion (€22.5 billion) aid package for Ukraine at risk.
What Biden said
"I'm counting on the good judgment of the United States Congress. There's no alternative," Biden said when asked by a reporter whether Congress would pass the funding.
Biden commented as he received Ukrainian President Volodymyr Zelenskyy at the White House and spoke of the long-term commitment to Ukraine's security.
Biden hailed "the brave people of Ukraine" and said they had been an inspiration to the rest of the world adding: "The American people are determined to see to it that we do all we can to ensure the world stands with you."
Biden said he had approved a fresh tranche of security aid, which the Pentagon later valued at $325 million, and that the first US M1 Abrams tanks would arrive in Ukraine "next week."
What the Ukrainian president said
Zelenskyy was seated with Biden beneath portraits of former US presidents George Washington and Abraham Lincoln, and thanked Biden for the support.
"We greatly appreciate the assistance provided by the United States to combat Russian terror, really terror," Zelenskyy told Biden.
"I started my day in the US Congress to thank his members and the people of America for that big, huge support. I felt trust between us, and it allowed us to have a frank and constructive dialogue, Mr. President."
The latest US round of help for Ukraine includes air defense missiles, ammunition for HIMARS precision rocket launchers, anti-tank weapons, and artillery rounds.
However, Zelenskyy's second visit to Washington since Russia launched its full-scale invasion of Ukraine in February 2022 came with the world focused on whether support for Ukraine from its allies might be ebbing away.
A hard-right wing of the Republican Party, led by former President Donald Trump, is increasingly opposed to spending more money to help Ukraine in its war effort.
Kyiv also encountered a setback when Poland said it would halt making new weapons pledges to its ally amid a trade dispute, although Warsaw has denied the two issues are linked.
kb,rc/jsi (dpa, AP, AFP, Reuters)