England manager Roy Hodgson and captain Wayne Rooney have appealed to fans to behave around Thursday's Group B game against Wales after European soccer chiefs threatened to throw the country out of Euro 2016 following three days of violence in Marseille.
In a video posted on the Football Association's Twitter page, Hodgson and Rooney expressed their concern that further flashpoints could lead to an early end to their tournament.
"As the England manager, I am obviously now very concerned about the threat that is hanging over us and the sanction that could possibly be imposed upon the England team," Hodgson said.
"We worked very hard to get here and we want to stay in the competition."
The first weekend of the tournament was overshadowed by violence in Marseille where English and Russian fans were involved in serious disorder, leading to tear gas and water cannons being deployed by French riot police.
European governing body UEFA have begun disciplinary proceedings against the Russian federation after some of their fans appeared to charge at England's fans in the Stade Velodrome near the end of the Group B clash that ended 1-1.
UEFA have warned English and Russian officials that their teams will be sent home if the trouble continues.
But there are fears that England and Russia fans could start fresh trouble this week. Russia play Slovakia in Lille on Wednesday, while England face Wales just 40 km away in Lens on Thursday.
"I'm appealing, therefore, to all of our fans, and we appreciated your support at the matches, of course, but I'm appealing to you to stay out of trouble to try and make certain these threats are never carried out and we will be able to do the best we can to stay in the competition," Hodgson said.
Rooney pleaded with fans to stay away from Thursday's match against Wales unless they have tickets.
"I'd like to ask the fans: 'Please, if you don't have a ticket, don't travel. And for fans with tickets: 'Be safe, be sensible and continue with your great support for the players.'"
Welsh fans were praised for their behaviour before, during and after their 2-1 victory over Slovakia in Bordeaux on Saturday but their match against England is another potential flashpoint.
"The aggression starts on the pitch and must remain on the pitch," Wales coach Chris Coleman said on Monday. "Off the pitch there should be no aggression. Unfortunately there is a mindless minority.
"What we want from our fans is to support us in the perfect way like they did in Bordeaux."
