Before the capital derby on Saturday, there were fights between fans of Roma and Lazio.
According to Italian media, about 200 Lazio fans and around 100 Roma fans clashed near the Stadio Olimpico in the morning.
Police had to intervene and use tear gas to stop the fighting. They arrested a 41-year-old man, who is said to be a Roma fan.
Authorities are checking security camera footage to find others involved. They also seized potential weapons like helmets, bats, sticks, and wrenches.
Roma is hosting Lazio on Saturday afternoon. Both teams are trying to qualify for Europe. Roma is in fifth place with more points than Lazio, which is in seventh place in Serie A.
