A suspicious package which prompted an alert at the US embassy in the Vatican has been found to contain stationery.
Italian bomb squad officials were sent to the Holy See but the embassy was not evacuated.
There has been heightened concern in Rome after two parcel bomb blasts at the Chilean and Swiss embassies in Rome on Thursday left two people hurt.
There have been a number of false alarms as embassy staff checked mail from the Christmas period.
An Italian anarchist group, Informal Anarchist Federation (FAI), said it was responsible for the bombs.
A third parcel bomb was found at the Greek embassy on Monday.