Inter Milan's match with Lazio was postponed today and AC Milan's game at Atalanta was abandoned early on after a Lazio fan was shot dead by a police officer.
AS Roma's late home match with Cagliari, due to kick off at 7.30pm, was also postponed, an Italian soccer federation spokesman said, quoting Rome's civil defence officer.
The Lazio fan, named as Gabriele Sandri, was killed during clashes with Juventus supporters at a service station near Arezzo, prompting the federation to postpone the San Siro match and delay the kick-offs of the other Serie A matches by 10 minutes.
Sandri was in a car with other Lazio fans, police said.
News of the fan's death filtered through to other fans and violence erupted before the Atalanta game with supporters scuffling with police in riot gear.
The match went ahead but a small group of fans, covering their faces with scarves, tried to smash a glass barrier keeping them from the pitch, prompting the players to leave the field in the seventh minute.
The game was abandoned 40 minutes later with players telling media that the fans had threatened to cause more trouble if the game had re-started.
A match in Italy's third tier at Taranto was also suspended because of fan violence, media reported.
Roma general manager Rosella Sensi told reporters that fear of more violence was not the main reason for the request to postpone her side's game.
"In a sign of solidarity with Lazio fans and all the city of Rome grieving the death of Gabriele Sandri, it is right to ask the postponement of the game this evening in the Stadio Olimpico against Cagliari," she said.
Italy coach Roberto Donadoni was still scheduled to name his squad for the crunch Euro 2008 qualifiers with Scotland and Faroes Islands later today.
Italy has been trying to crack down on fan violence since a policemen was killed in riots outside Catania's match with Palermo last season. The league was suspended for a period following the death and strict new safety rules brought in.
The other top-flight matches on Sunday were played without serious incidents but there was an eerie atmosphere inside the stadiums, where fans took down team banners as a mark of respect.
Inter remain top, despite not playing, with second-placed Fiorentina losing 2-1 at home to Udinese, their first defeat in 21 games in all competitions since April.