The Celtic chairman Brian Quinn has urged supporters not to sing "songs and chants that are offensive to the great majority" as they prepare for their Champions' League campaign.
Uefa, football's European governing body, has threatened clubs with disciplinary action as it clamps down on racism, bigotry and sectarianism. That prompted Rangers to step up their campaign against these problems and now Celtic have followed suit.
The Scottish Premier League champions travel to Old Trafford next week to face Manchester United in the Group F opener, and that has prompted a tough message from the club. Quinn said: "We mustn't throw away our chances of success through the misbehaviour of a small number of people who may follow our team but cannot really be called supporters if they continue to jeopardise our progress in Europe by singing songs and chants that are offensive to the great majority of our supporters. Do they really want to see Celtic penalised by the football authorities, with the possibility of having points deducted or even European games having to be played away from Celtic Park? I think the answer to that is obvious.
"I have received many letters on this matter. The great majority fully support the stance taken by the club. A very few have argued that we are interfering with their right to free speech or that they do not need lectures from the likes of me on how to behave.
"Both these comments are wide of the mark. The right of free speech has to be balanced against the rights of others, especially in this case those who find the songs and chants in question unacceptable and damaging to Celtic's good name. I don't do lectures. As my recent letter shows, I do appeals to supporters' sense of good behaviour.
"Finally," Quinn added, "this is not a message intended only for European games. It applies equally to domestic matches, at home and away. Let's create an atmosphere that all Celtic supporters can enjoy as we follow and support our great club."
Meanwhile, the Celtic manager Gordon Strachan has hit back at critics who have questioned whether the club's newly acquired Danish international, Thomas Gravesen, and Neil Lennon can play together in the same midfield.
Gravesen should make his debut against Aberdeen on Saturday following his move from Real Madrid. But some expected his arrival to signal the end of the 35-year-old Northern Irishman Lennon's Celtic career, suggesting the pair were too similar to play in the same midfield.
Lennon argued last week that they could be a success together this season. And Strachan said: "People who say that do not know the game and do not know Thomas Gravesen. They are ill-informed to start with - and people said that about Roy Keane and Neil Lennon.
"But other people are paid to talk and if that is their only ability then carry on. I don't have a problem with that.
"Roy Keane joined us and people said, 'He and Lennon can't play together', but when he joined we were about four points ahead in the title race. They went on to play together and when we won the league we were 20 points ahead.
"Anybody with any intelligence can look at it and say, 'Thomas Gravesen is an all-round midfield player', and anyone who says that 'he is a sitting midfielder like Neil Lennon' hasn't done their homework, does not know the game, does not know Thomas Gravesen, and if we are going to have opinions then let's have educated opinions," the Celtic manager said.Reuse content