EKATERINBURG, December 17 (Reuters): A super heavyweight title fight between Russian boxer Alexander Povetkin and Haitian-born Canadian Bermane Stiverne that was scheduled for Saturday has been canceled after Povetkin failed a drug test. Povetkin's promoter Andrei Ryabinsky wrote on Twitter that the Russian boxer had tested positive for the banned muscle-building substance ostarine. Povetkin was to fight Stiverne for the World Boxing Council (WBC) interim world title in the Russian city of Ekaterinburg. WBC president Mauricio Sulaiman said on Twitter the WBC was officially withdrawing recognition of the Povetkin-Stiverne fight due to Povetkin's drug test.