UEFA have opened disciplinary proceedings against Celtic for the display of an "illicit banner" during the Champions League match with AC Milan on Tuesday night.
The governing body's Control and Disciplinary Body will deal with the case on December 11.
On the banner, unfurled before the match, images of William Wallace and Bobby Sands were shown alongside the message: "The terrorist or the dreamer? The savage or the brave? Depends whose vote you are trying to catch or whose face you're trying to save."
UEFA's disciplinary code says clubs may be subject to disciplinary measures if supporters are found to have used "gestures, words, objects or any other means to transmit any message that is not fit for a sports event, particularly messages that are of a political, ideological, religious, offensive or provocative nature".
The governing body told STV: "Disciplinary proceedings have been opened against Celtic FC for an incident of non-sporting nature at their UEFA Champions League match with AC Milan."
In response to the charge, Celtic and their chief executive, Peter Lawwell, issued an angry statement criticising the conduct of a "small minority" and the impact it is having on the club.
"Last night was nothing more than clear disrespect for the club and our supporters who now face another UEFA charge," said Lawwell.
"There have now been a number of UEFA charges made against the club during the last three years, relating to behaviour, displays and pyrotechnics. It cannot go on any further.
"Let´s be very clear. Following the actions of a small minority, these charges are made against the club.
"It is the reputation of Celtic, our great club and our great fans which is damaged, while others carry on indulging in such behaviour.
"Our supporters do not want this any more. We are a non-political organisation, a top football club in fantastic shape, aiming to play its part as a major football club on the European stage.
"Regardless of the political views people hold, football stadia, whether it is Celtic Park or anywhere else, should not be used to promote these.
"This is something which all football authorities, including UEFA, have stressed for some time and something well known by all supporters.
"The club don’t want it, our manager and our team don´t want it, our supporters don’t want it and the football authorities don’t want it. It has to stop.
"Celtic is a world-class football club and rightly proud of its wonderful reputation in the game. This is a reputation hard-earned by our supporters over many years. We cannot and will not allow this reputation to be tarnished any further."
A statement from the club read: "During the last two matches at Celtic Park, banner displays have taken place which have not been approved by Celtic Football Club.
"These were displays which were in no way football-related and which have no place at Celtic Park.
"Celtic Football Club can confirm that any individual or group identified as being involved in any form of political display at a match involving Celtic will be banned immediately from attending matches involving the club.
"With regard to last night´s display, the club made it abundantly clear in advance to the group in question that only football-related displays would be permitted and that any political display would lead to a UEFA charge.
"We, in turn, received an assurance that all displays would be 100% relevant to Celtic. Therefore, the actions of this group are clearly very disappointing. We have been inundated with complaints from Celtic supporters regarding the display.
"Celtic does more now than it ever has to liaise with and support the numerous fans' groups which exist.
"We have encouraged and facilitated all groups and their support for the club through various initiatives. It is clear, however, that by some at least this courtesy has not been reciprocated."
Celtic were fined £4,221 earlier in the season by UEFA after fireworks were set off by supporters during their Champions League qualifier with Cliftonville.
The club's fans also caused them to be fined twice during their Europa League campaign in the 2011/12 season.
In March 2012, UEFA fined Celtic £21,000 after supporters displayed an offensive banner and set off flares during an away game with Udinese.
Celtic were also fined £13,000 for "illicit chanting" in the same competition during a match with Rennes.
Police Scotland are also investigating after a laser pointer was allegedly used on AC Milan goalkeeper Christian Abbiati during Tuesday's match.
Although UEFA rules allow for action to be taken on such a case, the governing body have not stated they will act.
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