Two Celtic fans have been stabbed by Lazio supporters and hospitalised ahead of the teams' Europa League match this morning.
Italian police say the stabbings occurred in downtown Rome following a brawl outside a pub.
Police also say two Celtic fans were stopped for resisting police and a third fan was stopped for obscene acts.
Also, five Lazio fans were stopped for possession of dangerous materials such as baseball bats and knives at an event featuring fans of both clubs.
Some 9,000 Celtic fans were slated to attend the match at the Stadio Olimpico.
One end of Lazio's stadium will be closed for the match as punishment by UEFA for racist incidents at a previous game against Rennes.
UEFA also opened disciplinary cases against Celtic and Lazio after fans traded anti-fascist and fascist gestures during Celtic's 2-1 win in Glasgow last month.
Celtic won this morning's match 2-1 after Olivier Ntcham scored the game-winner in the fifth minute of injury time.