Zenit St Petersburg have launched an investigation into an alleged incident of racist abuse involving former Brazil left-back Roberto Carlos.
The 37-year-old, who now plies his trade for Russian outfit Anzhi Makhachkala, was apparently taunted by Zenit fans prior to his side's 2-0 defeat to the reigning Premier Liga champions on Monday.
A photograph has since emerged of a supporter appearing to wave a banana in the direction of the former Real Madrid star as the two teams entered the field.
Zenit have condemned the alleged incident, and vowed to step up their efforts to stamp out racism by working closely with the country's governing body and the police.