Anti-Mafia groups expressed outrage on Monday after learning that five bosses, including three convicted of the 1992 murder of top Sicilian magistrate Paolo Borsellino, were to be given softer jail terms.
The association for the relatives of Mafia victims said the decision was "unbelievable" and demanded an explanation from Justice Minister Clemente Mastella.
Sicilian daily Il Giornale di Sicilia reported in a Monday article that Mastella had written to anti-Mafia prosecutors informing them that the period of tough jail conditions prescribed for the five bosses had lapsed.
The daily named the five as Salvatore Biondo, Giuseppe Montalto, Lorenzo Tinnirello, Salvatore Benigno and Cosimo Lo Nigro.
Biondo, Montalto and Tinnirello are all serving life for the July 1992 car bombing which killed renowned anti-Mafia prosecutor Borsellino and five members of his escort.
Benigno and Lo Nigro have been jailed for life for their part in a May 1993 car bomb attack in central Florence which killed five people, injured scores of others and damaged the famous Uffizi art gallery.
Until now, the five mafiosi have been subject to very strict jail conditions as laid down by the article '41-bis' of Italy's criminal code for Mafia bosses and terrorists.
Such prisoners are kept in single-person cells in maximum-security jails, almost entirely cut off from the outside world.
Il Giornale di Sicilia said that in order for the five bosses to be put back under a 41-bis regime, magistrates would have to prove that they were in contact with Mafia members on the outside.
Rita Borsellino, the sister of Paolo Borsellino who entered politics after her brother's slaying, commented: "41 bis is not a vendetta by the State but a precautionary measure to prevent those who have been condemned for serious crimes from maintaining contact with the outside and continuing to run their clans.
"The fact that a mafioso could be released from such measures simply because a deadline has expired is intolerable".
An association representing the families of the victims of the Florence bomb attack stressed that 41-bis was the "only prison regime suitable for the mafiosi who planned and carried out the 1993 bombing".
It argued that the State was sending out the wrong message to Cosa Nostra, apparently yielding to its long-standing bid to get 41-bis abolished.
The police union SAP was also indignant, saying that "it is inconceivable that the tough prison terms for these five bosses have been allowed to lapse".
"Episodes such as this indicate the extent of the State's determination to combat the Mafia," the union said.
The deputy head of parliament's anti-Mafia Committee, Giuseppe Lumia, also expressed alarm.
Lumia said that too many mafiosi were successfully appealing to parole review boards against their tough prison conditions.
National anti-Mafia prosecutor Piero Grasso warned last week that the number of mafiosi subject to 41 bis was falling sharply.
In a report to parliament, Grasso said that 200 bosses had seen their prison conditions eased since 2003 and that only 521 bosses were currently being kept in isolation.
He said 93 mafiosi were released from 41 bis in 2006 and 12 last month alone.
Grasso said that part of the problem was the need to prove that bosses were in contact with outside mafiosi in order to extend the application of 41 bis.
Even former Cosa Nostra superboss Salvatore (Toto') Riina has asked to be granted softer jail terms while he serves out 12 life sentences.
The 76-year-old ex-'boss of bosses' unsuccessfully appealed for the tough conditions of his incarceration to be lifted on health grounds.
The 41 bis was first introduced after the murders of Borsellino and another top anti-Mafia magistrate, Giovanni Falcone.
Initially, it was a temporary measure that had to be renewed on an annual basis.
In 2002, under the then government of Silvio Berlusconi, the measure became a permanent fixture in the penal code.
However, there have been several scandals over Mafia bosses who have been found to be running their affairs from the inside despite being in supposed isolation.
In 2004, jailed bosses Vito and Leonardo Vitale were discovered to be communicating with each other and sending orders to members of their crime family on the outside.
Investigators said the two brothers sent out commands regarding the management of public works contracts in Sicily and protection money payments from local businesses.
Leonardo Vitale was even able to send faxes to his wife and family with coded messages.
Shocked lawmakers said the incident showed that the 41-bis was not strict enough.
