ROME — There might be an addition to Italian soccer stadiums if fan violence persists: jail cells.

"If it's necessary, let's build cells in stadiums to jail immediately whoever commits a crime," Italian league president Antonio Matarrese said today.

The suggestion comes after a violent opening weekend to the Serie A season. Napoli fans caused a riot on a train to Rome, and more violence broke out when the train reached the capital for the AS Roma-Napoli game.

Two seasons ago, a police officer was killed outside Catania's stadium in riots following a game with Sicilian rival Palermo. Last year, a Lazio fan was killed by police at a highway rest stop.

The Interior Ministry on Thursday unveiled an ad campaign against soccer violence, with spots to be broadcast on TV and stadium screens.

"We will continue to fight against violence without letting our guard down," Matarrese said. "The (club) presidents are doing the impossible. Let's not forget that some go around with security escorts because they face opposition from violent fan groups."