England manager Roy Hodgson and captain Wayne Rooney have appealed for fans to support the team in the best possible manner ahead of Thursday's Euro 2016 clash with Wales.
Chief executive Martin Glenn issued a statement on Sunday after UEFA contacted The FA following disorder at the Group B opener between the Three Lions and Russia.
Hodgson said: "As England manager, I'm obviously very concerned about the threat which is now hanging over us of sanctions that could be imposed upon the England team.
"We've worked very hard to get here, and we really desperately want to stay in the competition. We appreciate your support at the matches of course, but I'm appealing to all of our fans to stay out of trouble and to try to make certain that these threats that are being issued are never carried out so we can attempt to do the best we can to stay in this competition by football means."
Rooney added: "I'd like to thank the England fans for the great support inside the stadium against Russia.
"Now, as we have a big game coming up against Wales, I'd like to ask the fans that, if they don't have a ticket, please don't travel. For the fans with tickets: be safe, be sensible and continue with your great support for the players."