Any plan to confiscate or monetize $300 billion in frozen Russian assets in favor of Ukraine cannot be seen as a substitute for urgently needed aid that has been delayed in Congress. This was stated by US Treasury Secretary Janet Yellen, Bloomberg reports.

"I don't see any real substitute for Congress providing Ukraine with the aid it needs this year. I don't think anyone can fill that gap," she said.

Although the European Union has offered Ukraine "very significant funding" and Japan has also contributed, "the total amount seems insufficient," Yellen said. The funds could help the country cope with the situation in the near future while Kyiv is waiting for more comprehensive assistance, she said.

More than $60 billion in proposed US emergency aid to Ukraine has been stuck in Congress for months as Republicans try to force President Joe Biden to change immigration policy. Yellen warned that without the aid, Ukraine could face serious difficulties.

Yellen acknowledged Europe's concerns over the confiscation of Russian assets, but said her colleagues were open to working with the United States.

"Once they heard that we think there's a good international case and that we can look for alternatives to try to mitigate the various risks, they're certainly willing to work with us," she said.