Celtic fans in Rome have reported being attacked after a shuttle bus taking them back from the stadium broke down.
Supporters said they were "ambushed" as they had to walk back into the city following Celtic's 2-1 victory over Lazio.
It comes after two Celtic fans were stabbed by masked attackers outside a pub in Rome the night before the match.
Fans took to social media to describe how they were attacked as they returned from the stadium on Thursday evening.
Michael McFarlane tweeted a video of fans walking in the dark and wrote: "Our shuttle bus broke down 1km from the stadium. Driver chucked us out, meaning we had to walk through the Lazio neighbourhood.
"After this video, about 20 Lazio fans sprinted from the dark and ambushed the group at the river. Got away safe, not sure about others."
Rab Robertson wrote: "Fair squad of us ambushed, weans the lot, completely co-ordinated, hopefully all safe", while Thomas Lunday tweeted: "Not enough buses to take everyone back to the city, so rest of the fans had to walk a couple miles further on that's when they where ambushed by casuals."
The Celtic fan liaison officer advised fans to "keep a low profile" as they returned from the game.
He tweeted: "Wee update for fans in Rome, don't walk back to town, get taxis or shuttle buses back to the city and keep a low profile."
The club had issued safety advice to fans amid tensions after a match between the clubs in Glasgow last month.
Supporters were 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 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.