The Austrian Raiffeisen Bank, part of an industrial combine that underpins Austria's economy, is the biggest Western bank in Russia. Washington is facing stiff resistance from Austrian politicians and officials, some of whom have defended Raiffeisen.

Although Austria publicly supports Ukraine, several officials say they are reluctant to completely sever decades-old ties with Russia, thinking it will still be possible to restore relations.

Recently, Austria pressured Ukraine to suspend Raiffeisen from an Ukrainian blacklist, holding out on backing fresh European Union sanctions on Russia until they did, people familiar with the situation said.

Austria and the bank wanted it to be taken off a Ukrainian list dubbed "international sponsors of war" - which sets out to shame companies doing business in Russia and supporting the war effort by, for instance, paying taxes.

Vienna remains a hub for cash from Russia and its former Soviet neighbours and Austria maintains close ties with Russia through critical gas pipelines and finance.