Italian police say they have arrested nearly 100 people in anti-Mafia raids across the southern island of Sicily and in the central region of Tuscany.
They say the operation targeted the bosses of local clans who were planning to rebuild the Sicilian Mafia - also known as Cosa Nostra.
A police statement said the raids involved some 1,200 police officers.
The Sicilian Mafia was dealt a huge blow with the arrest in 2006 of its boss Bernardo Provenzano.
The police operation, codenamed Perseus, involved the use of helicopters and dogs in a vast sweep across Italy, says the BBC's Duncan Kennedy in Rome.
Police said it was the result of a nine-month operation that included the use of phone taps.
Those being held are accused of extortion, arms dealing and drugs trafficking.
Loss of influence
The police statement said that Matteo Messina Denaro, alleged to be one of the mobsters trying to become the overall leader, was behind the plan to set up a Mafia council with the aim of appointing a new godfather, to re-establish the Cosa Nostra's influence.
Provenzano was arrested in April 2006 after 43 years on the run
That has been on the wane since Provenzano - who is also known as the "Boss of Bosses" - was arrested in April 2006 after 43 years on the run.
After his arrest Provenzano was believed to have handed the reins of the Cosa Nostra to a younger man, Salvatore Lo Piccolo.
He was arrested in November 2007, and police say they are still not sure who is now heading the Cosa Nostra.
But analysts believe that other mafia organisations on the mainland, including the 'Ndrangheta and Camorra, have increased their presence in organised crime both in Italy and in other countries.
For many years, the Mafia's core criminal activity has concentrated largely on protection rackets and the construction business. It is also involved in drug trafficking and money laundering.
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