Two Celtic fans are in hospital after they were stabbed in Rome.
The incident happened outside the Flann O’Brien pub in the Italian capital on Wednesday night.
Celtic are due to play Lazio in a Europa League clash at the Stadio Olimpico on Thursday evening.
Italian police said the injured pair were taken to hospital for treatment.
Celtic had issued safety advice to fans amid tensions after a match between the clubs in Glasgow last month.
Supporters are advised to avoid wearing club colours while walking around Rome, particularly in the evening, stay in large groups where possible and keep a low profile.
The club said: “There will be a prominent police presence throughout the city on the day prior to the match and on match day. Fans are advised to always follow the advice of police at all times.”
The Glasgow club and Lazio were charged by Uefa over “illicit chants” heard during their Europa League match on October 24.
Celtic were also charged over the display of an “illicit banner” during the game, which they won 2-1.