UEFA has opened disciplinary proceedings against Chelsea on a charge of racist behaviour relating to antisemitic chants by their supporters in a Europa League group match against Vidi in December.
The match, which ended 2-2, was marred from the opening minutes by reports on social media of antisemitic chanting coming from the section of Groupama Arena that housed the 1,273 Chelsea supporters who had travelled to Budapest.
Chelsea now face the possibility of a partial closure of Stamford Bridge for a future UEFA match, though any punishment will come too late to affect their round-of-32 tie against Swedish giants Malmo next month.
A UEFA statement read: "Based on the report submitted by the UEFA Ethics and Disciplinary Inspector commissioned to conduct an investigation -- according to Article 31 (4) of the UEFA Disciplinary Regulations (DR) -- in relation to the alleged racist incidents that occurred at the afore-mentioned match, UEFA has announced that disciplinary proceedings have been instigated against Chelsea FC in accordance with the Article 55 of the DR.
"The UEFA Control, Ethics and Disciplinary Body will deal with this case on the occasion of its next meeting on 28 February 2019."
Shortly after the game a Chelsea spokesman condemned the chants of a minority of supporters at Groupama Arena, claiming they had "shamed the club."
News of UEFA's action comes a week after Metropolitan Police confirmed that three men had been arrested on suspicion of antisemitic chanting prior to Chelsea's clash with Tottenham in the first leg of the Carabao Cup semifinal at Wembley. A 23-year-old man has been released under investigation.
The prospect of UEFA punishment for antisemitic chanting is particularly embarrassing for Chelsea, who have gone to great lengths in their attempts to eradicate antisemitism from football since launching a targeted campaign at the urging of owner Roman Abramovich in January.
Holocaust survivor Harry Spiro was invited to Cobham to address the first-team squad in January, while Chelsea sent a delegation to attend the annual March of the Living at Auschwitz in April.
This was followed in June by an official visit, consisting of 150 supporters and club officials, to the Nazi concentration camp.
Last month Chelsea announced that they will play MLS club New England Revolution in a postseason friendly, branded "Game for Change," as part of their campaign against antisemitism.
Abramovich and Revolution owner Robert Kraft, who are both Jewish, have pledged to donate $1 million (£778,565) to the fight against antisemitism, with all money from ticket sales also going to the cause.