Wales fans without tickets for Thursday's Euro 2016 match against England have been urged not to travel to host city Lens or nearby Lille.
Wayne Nash, national security officer of the Football Association of Wales (FAW), said supporters should "enjoy the match" wherever they were.
Discussions have taken place about having a British police presence inside the Stade Bollaert-Delelis in Lens.
It follows the violent scenes that marred England's game against Russia.
Nash, speaking to BBC Wales Sport, told fans: "If you do not have a ticket, do not go to Lens for the game.
"Enjoy the match if you are in France, whether in the south of France in the bars or restaurants or in the campsites. And if you are in Wales, stay at home and don't travel to the game without a ticket."
Lille, which is 24 miles from Lens, hosts Russia's second Group B game, against Slovakia on Wednesday.
Nash added: "We have never advised our fans to go to Lille. Our advice was always to go to Arras or Amiens.
"Of course, with the fact Russia play Slovakia the day before, I'm cognisant of what happened on the weekend. It just makes our advice more pertinent really."
The FAW and the English Football Association are hoping there will be some British police presence inside the stadium on Thursday.
Police from both countries discussed the situation on Monday and will now hold talks with the prefect of Lens and Uefa's head of security.
Nash said: "Thursday's game has a very British feel to it and we have talked about deployment of officers. We think it would be reassuring to have officers in and around the stadium. Our fans are used to it.
"It's not the French way but we think on this occasion, and following the events at the weekend, our fans would be reassured."
Nash emphasised Wales supporters had been praised for their behaviour before, during and after Saturday's 2-1 win over Slovakia.
"We had a great day in Bordeaux, our fans behaved impeccably - that is well documented and evidenced," he said.
"We want them to come and enjoy the game, enjoy the occasion, get behind the boys and be as passionate as they were at the Slovakia game. But just be aware we have to keep things the right side of decent."