UEFA has released a statement saying that Russia and England could be disqualified from Euro 2016 if their fans are involved in more violence.
Numerous clashes between individuals appearing to be supporters of either of the two teams have taken place in Marseille over the last few days.
In addition, a number of Russian fans were filmed charging at England fans at the Stade Velodrome after their Group B game, which finished 1-1.
The UEFA executive committee released a statement on Sunday warning both countries that, on top of any sanctions over trouble in Marseille this weekend, "it will not hesitate to impose additional sanctions on the Football Association (FA) and the Russian Football Union (RFU), including the potential disqualification of their respective teams from the tournament, should such violence occur again".
The European football governing body has also begun disciplinary proceedings against Russia - but not England - after "totally unacceptable" scenes at Saturday's game.