Russian football hooligans have defied the police and country's security services to stage an ugly brawl in a World Cup host city just six weeks before the start of the international contest.
Video footage has emerged of a violent clash between “Ultra” fan groups linked to Zenit St Petersburg and CSKA Moscow.
The footage was deliberately low quality to prevent perpetrators being identified by the Russian authorities.
The battle involving around 50 thugs throwing punches and kicking was ahead of a 0-0 draw between the two clubs in St Petersburg on Sunday.
It will be seen as a warning to foreign fans travelling to the FIFA World Cup in June.
England's base for the contest is close to St Petersburg, Vladimir Putin's home city.
Putin has ordered a crackdown on perpetrators of football violence - and especially hooligan leaders - to prevent trouble at the showcase tournament which kicks off on Thursday, June 14.