Professional boxing's British governing body said on Thursday it would not allow boxers registered or licensed in Russia and Belarus to fight in Britain.
The British Boxing Board of Control's statement follows global sporting sanctions in response to Russia's invasion of Ukraine.
No major professional fights in Britain are currently scheduled involving boxers from Russia or Belarus.
Russian light-heavyweight world champion Dmitry Bivol is due to fight Mexican Saul "Canelo" Alvarez in a high-profile WBA title fight in Las Vegas on May 7, a bout that has faced calls for cancellation.
Ukraine's former world heavyweight champion Wladimir Klitschko, whose older brother Vitali is mayor of Kyiv, told the BBC this week that the fight should not be allowed to proceed.