The leaflet voiced solidarity with Cospito, 55, the head of the Informal Anarchist Federation (FAI) who has been on a hunger strike for more than 100 days against his tough 41 bis prison regime, normally reserved only for mafia bosses.

It accused the state of torturing the FAI chief, who has lost almost 50 kg on his hungers trike and whose heart is being constantly monitored amid fears for his life.

Cospito has, however re-started taking dietary supplements again after Cassation prosecutor general, Pietro Gaeta, said the state should revoke the jail regime.

Justice Minister Carlo Nordio has said Cospito must stay under the 41 bis regime because he is capable of leading anarchists from jail, but the supreme Court of Cassation is expected to lift it, for him alone, on February 24.

The FAI leader is campaigning for the end of 41 bis for all inmates including mafiosi.

Thursday's leaflet was sent to, among others, a manager of a Turin-based firm, the sources said.

The fresh anarchist threats are a phenomenon that has already been seen time and time again, Interior Minister Matteo Piantedosi said on Thursday.

"The episodes of the anarchist letters with bullets sent to companies and managers are being investigated, but they are already-seen modalities on which the police have an already high level of attention," he said.

"However, we must always send out very balanced messages, not of underestimation of course, but neither must we make people worry (unduly).”

FAI members have been staging violent protests and arson attacks inside and outside Italy backing Cospito's campaign.

In related news, Justice Undersecretary Andrea Delmastro has been put under investigation by Rome prosecutors in relation to revelations made in parliament about the case of Cospito by Giovanni Donzelli, a fellow MP for Premier Giorgia Meloni's Brothers of Italy (FdI) party, sources said on Thursday.

The probe was opened after Angelo Bonelli of the Green and Left group filed a complaint, but does not mean Delmastro will face charges.

Donzelli revealed that Cospito had talked to mafia bosses about getting the 41 bis abolished.

He also revealed that four lawmakers from the centre-left Democratic Party (PD) had visited Cospito in jail.

During the debate Donzelli, a member of the Copasir parliamentary committee that oversees Italy's intelligence services, asked whether the PD was on the side of the State or that of the mafia and terrorists.

Delmastro, who is also Donzelli's flat mate, was the source of the information.

Justice Minister Carlo Nordio has said that the information was not classified.

ANSA