Italian special forces stand outside their headquarters in Palermo after a 'historic' sweep against mafia clans in Palermo and Tuscany early on Tuesday. (Marcello Paternostro/AFP/Getty Images)

Italian police backed by helicopters arrested almost 100 suspected mobsters Tuesday and thwarted a plan by the hobbled Sicilian Mafia to reconstitute itself and form a new ruling commission to set strategy, authorities said.

Carabinieri police in Palermo said the operation there and in other Sicilian cities was one of the largest in recent years and gave investigators a picture of the new highest echelons of the Mafia. It also prevented possible bloodshed as bosses vied to control the commission.

The raids involved 1,200 police officers and helicopters.

They targeted the bosses of local families and lower-level mobsters intent on setting up the commission, which was to make Cosa Nostra's important decisions such as possible attacks, police said.

Salvatore (Toto) Riina, the boss of bosses, famously headed such a commission, known as the "cupola," until his arrest in 1993. The commission decided to carry out a strategy of all-out attack against the state that culminated with the back-to-back slayings of top anti-Mafia fighters Giovanni Falcone and Paolo Borsellino in 1992.

The Mafia's hierarchy has been trying to overcome disarray in its ranks since Riina's successor, Bernardo Provenzano, was arrested in April 2006 and Provenzano's closest aides two months later.

"If that operation … brought Cosa Nostra down to its knees, this prevented it from getting up again," Pietro Grasso, the national anti-Mafia prosecutor, told ANSA on Tuesday.

The operation — called Perseus, after the Greek mythological hero who beheaded Medusa — "severed all the strategically important heads of a new ruling structure that had to deliberate, as it once did, on all serious acts," Grasso said.

The current attempt to restore the commission was masterminded by a suspected mobster, Matteo Messina Denaro, who is among a handful of people vying to replace Provenzano, police said.

Messina Denaro is seen by investigators as a top candidate for the job after his main competitors were arrested. He remains at large.

Charges for those arrested Tuesday include Mafia association, extortion, arms and drug trafficking, the Carabinieri said in a statement.