US president warns of further losses of Ukrainian territory if Congress does not renew military aid.

“I spoke with Zelenskyy this afternoon to let him know that I was confident we’re going to get that money,” Biden told reporters on Saturday.

Biden said he was not confident another Ukrainian city would not fall to Russian forces without US support and that it would be  “absurd” and “unethical” for lawmakers not to approve a new package of military aid.

“I find it contrary to everything we are as a country,” he said.

Biden spoke to Zelenskyy in a call hours after Russia announced the capture of Avdiivka following the earlier withdrawal of Kyiv’s forces, which the Ukrainian leader described as “a professional decision that will save many Ukrainian lives”.

Russian President Vladimir Putin hailed the capture of Avdiivka, an industrial hub located some 10km (6.2 miles) north of the city of Donetsk, as an “important victory” in the war, which is nearing the two-year mark.

The White House said in a statement after the call that Ukrainian forces withdrew after being forced to “ration ammunition due to dwindling supplies as a result of congressional inaction, resulting in Russia’s first notable gains in months”.

Zelenskyy said in a post on Telegram after the call that he was “glad that I can count on the full support of the American president” and that he had faith in the “wise decision of the US Congress.”

US Vice President Kamala Harris also took aim at Republicans for holding up aid on Saturday, accusing them of “political gamesmanship” after meeting with Zelenskyy on the sidelines of the Munich Security Conference in Germany.

Democrats and Republicans have been sharply divided over continuing support for Kyiv, with allies of former US President Donald Trump insisting the funds be spent on domestic issues, including border security.

While the US Senate passed a $95bn package of aid for Ukraine, Israel and Taiwan earlier this week, the bill faces a difficult road in the Republican-controlled House of Representatives.

Republican House Speaker Mike Johnson has slammed the bill for not addressing security on the US-Mexico border, which he has described as the “most pressing issue facing our country”, and insisted the House will not be rushed to approve the aid.

On Friday, Biden blasted House Republicans for taking a two-week recess, saying it was “time they step up” and assuage concerns about the US being a reliable ally.