Lazio and Roma fans launched flares at each other inside the Olympic Stadium before their Italian Cup quarter-final tie on Wednesday.
Videos from the stadium show fans from both sides throwing flares at one another in the stands.
Loud bangs could also be heard inside the ground as firecrackers exploded.
Despite the turbulent atmosphere in the stands, the players continued to warm-up on the pitch.
There was also an incident during the game where a Roma player was hit on the back of the head with a beer bottle after he was substituted.
Lazio beat Roma 1-0 and will face Juventus in the two-legged semifinals in April.
