German hooligans became the latest to join street battles that have marred Euro 2016. The French government gave police chiefs new powers to ban alcohol sales and consumption around stadiums.
The UEFA warning followed three days of violence in Marseille involving Russian and English fans, culminating in incidents inside the Stade Velodrome after Saturday’s 1-1 draw between the countries.
Thirty-five people were injured in the worst violence at an international tournament since the 1998 World Cup in France. Three remained in serious condition.
With more high-risk matches looming, the UEFA executive committee made a public “warning” to the two countries and expressed “disgust” at the clashes.
UEFA has laid charges against Russia, accusing their fans of crowd disturbances, racist behaviour and throwing “fireworks” and “missiles” in the Marseille stadium.
A decision on sanctions is to be announced Tuesday.
The UEFA executive committee also said “it will not hesitate to impose additional sanctions” on England and Russia, “including the potential disqualification of their respective teams from the tournament, should such violence occur again”.