(CNN) Several Italian mafia bosses have been released from prison under a new coronavirus regulation, the country's national anti-mafia prosecutor said.

Francesco Bonura, an influential boss in the Sicilian Cosa Nostra; Vincenzo Iannazzo, a member of the Ndrangheta; and Pasquale Zagaria, a member of the Casalesi clan, have now been moved to house arrest, according to Federico Cafiero De Raho, Italy's anti-mafia prosecutor.

To prevent the spread of the novel coronavirus within correctional facilities, the Italian government authorized magistrates to transfer inmates who have 18 months or less in their sentences to house arrest.

Cafiero De Raho said the three men had been held under "extra isolation measures" to avoid contact with people outside the prison because of the roles they had in mafia organizations.

"Once they are sent back home, these measures are obviously no longer enforced," the prosecutor added.

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