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 were arrested last night by the police in Cascal Bruciato, which is "a neighbourhood where an event was being held in a social centre for Celtic fans" ahead of the Europa League clash on Thursday night.
Eyewitnesses are reported to have said that the Celtic supporters were minding their own business up until the point they were set upon by the masked men. The pub's staff and Celtic supporters quickly took the injured men inside the pub while waiting for the ambulance.
"Again we would strongly advise supporters to closely follow all guidance issued by the club". Both will receive every support from the club and the British consulate in Rome.More news: Wildfires in eastern Australia pose an 'unprecedented' threat
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But he admits Lazio will need to take to the pitch with the mindset of getting a win in any way possible and feels the game is nearly like a final for the Serie A giants.
Celtic and Lazio were charged by the UEFA after their game in Glasgow on October 24 over illicit chanting. Lazio supporters were also seen performing fascist salutes before and during the game, which Celtic won 2-1.
In doing so, the Hoops avoided defeat in their opening three games of a Europa League campaign for the first time since 2014-15 and will hope to remain unbeaten when they visit Rome for tonight's second-leg.
That was Lazio's most recent defeat and subsequent appearances in Serie A have been impressive - victories at Fiorentina and AC Milan and a home win against Torino moved Simone Inzaghi's players to fourth place in the table, one point behind their city rivals, Roma.