The Football Association of Wales has warned supporters not to travel to Lille or Lens if they do not have a ticket for their Euro 2016 Group B match against England on Thursday.
Violence has marred the last three days of action at the tournament in France, and there are concerns that the trouble could continue.
England and Russia supporters clashed in Marseille prior to Saturday's 1-1 draw at the Stade Velodrome.
After the final whistle, Russia fans attacked their rival supporters in the stadium, which forced UEFA to open disciplinary proceedings against the national side.
England and Wales will go head to head in Lens on Thursday, the day after Russia take on Slovakia in the nearby city of Lille.
Ahead of the game, the Welsh governing body tweeted: "The FAW is advising fans not to travel to Lille and Lens for Thursday's match without a ticket."
UEFA has threatened to expel England and Russia from the tournament if violence continues.
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