Republic of Ireland boss Martin O'Neill has described the violence which has marred the start of the Euro 2016 as "tragic".
O'Neill and his staff have spent the last week preparing their players in Versailles, away from the trouble which saw parts of Marseille transformed into a battle zone before, during and after England's 1-1 draw with Russia.
UEFA have threatened the English and Russian football associations with disqualification if there is a repeat, and O'Neill admitted his shock at lurid television footage which has been beamed around the continent.
Speaking at his pre-match press conference ahead of Monday night's Group E fixture against Sweden, he said: "The scenes down in Marseille are pretty tragic.
"They're something that we thought we might not see for quite some considerable time at any part of the tournament, but to start off on that note, it's unedifying, it's pretty shocking.
"UEFA have come out and condemned it in very strong language and I think everybody feels the same. It's a poor start to the competition, I hope it can be rectified and sorted out.
"People are talking about maybe segregation wasn't strong enough, but do you know what? If people are setting out for trouble, I think they'll cause it regardless and from the pictures that we saw, it was pretty disconcerting."
Ireland skipper Robbie Keane admitted the prospect of being thrown out of the tournament because of the behaviour of so-called fans would be a cruel punishment for players.
He said: "If it cost you your place at the tournament, it would obviously be disappointing because you work so hard to get here as a team, as a nation and then you see something like this. It's not great to see.
"They let everybody down. You have to say there's only a select few that always ruin it for everybody else, so it's very, very disappointing to see."