United States President Joe Biden has said he assured Ukraine’s Volodymyr Zelenskyy that he is confident Congress will renew military aid to repel Russia after its forces captured the Ukrainian stronghold of Avdiivka.

''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.