Two Celtic supporters have been stabbed in the centre of Rome ahead of Thursday's Europa League match with Lazio.
Italian police confirmed that there was a brawl in front of the Flann O'Brien pub which was followed by the stabbing of a 52-year-old on Wednesday.
A 35-year-old was later attacked in Piazza Beniamino Gigli, not far from the pub. Both fans were admitted to the Policlinico Umberto I hospital with injuries that are not life-threatening.
An eyewitness has told Sky Sports News that a group of Celtic fans were drinking outside the pub when they were approached by four or five people wearing masks.
They added that a chair was thrown towards the Celtic fans leading to a fight that lasted around 15 seconds, during which time one person was stabbed to the side of his torso.
Celtic supporters and bar staff brought the victim inside the pub and they remained conscious while an ambulance was called.
The eyewitness said the crowd had been well behaved up until the incident took place.
5 things Celtic fans in Rome need to know— Celtic Football Club (@CelticFC) November 7, 2019
Do not make your own way to the stadium. Use the shuttle buses from 2pm at the Piazzele delle Canestre
Do not carry glass bottles or containers
Beer & food will be available at stadium
Avoid wearing club colours
Stay in large groups
Italian police said five Lazio fans and two Celtic supporters were arrested during the evening though it was not clear if they were all involved in the same incident.
One of the injured men remains in hospital while the other has been discharged.
In a statement on Thursday, Celtic confirmed they were aware of the incident and added that the two injured fans "will receive every support for the club and the British consulate in Rome."
Celtic had previously issued safety advice to fans amid tensions after the meeting 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.
Neil Lennon's side are top of Group E having won two and drawn one of their first three matches.