Palermo, 5 Nov. (AKI) - Italy's interior minister Roberto Maroni, its justice minister Angelino Alfano and two judges have received a letter threatening reprisals over the restrictive measures imposed on jailed senior mafia members. "You will pay and there will be blood," the letter reads.

Reportedly signed by relatives of jailed Sicilian mafia members, the letter was delivered to left-leaning daily La Repubblica's offices late on Wednesday in the Sicilian capital Palermo.

Italian police and prosecutors were on Thursday investigating the missive, which claims the restrictions placed on top mafia prisoners "are driving people to suicide."

"You will pay and there will be blood," it warns.

The letter was also sent judges Roberto Piscitello and Sergio Barbiera, as well as ruling conservative People of Freedom party MP Carlo Vizzini, a deputy from the opposition Democratic Party, Giuseppe Lumia, and two top civil servants in the justice ministry.

Lumia and Vizzini were among MPs who in July voted into law measures that toughened existing restrictions on jailed mafia bosses and other dangerous prisoners.

These include no phone access, solitary confinement and a ban on meetings or correspondence with other prisoners, limited visits by family members who are only allowed to communicate with prisoners through thick glass, and a ban on sending or receiving money or parcels.

In November, 2007, the European Court of Human Rights condemned Italy for the tough prison regime it imposes on its most dangerous criminals, known as the '41 bis'.

The Strasbourg-based court ruled unanimously that the so-called 41 bis regime violated two articles of the European Convention on Human Rights.