Prime Minister Silvio Berlusconi spent two nights sleeping at the office amid reports he was on a hit list of politicians held by an alleged terrorist, the Italian press said on Saturday.
The Italian government has refused to comment on or confirm the reports.
The newspaper Corriere Della Sera said it was rare for Berlusconi to sleep at his government office apartment and linked the move to the investigation of alleged terrorist Mohamed Game.
The Libyan, 35, lost his hand and eyesight after throwing a home-made bomb at the Milanese police barracks on October 12.
Game is suspected of planning other attacks on political figures after files on 15 politicians, including Berlusconi, were found on his computer, the Italian news agency Ansa said.
The Italian leader has not stayed overnight at his government apartment since 2003 when flu forced him to stay there for a few days.
The Chigi Palace is better protected than his own Grazioli Palace in Rome, and also avoids him making the one kilometre journey between the two buildings.