Bomb disposal experts have defused a parcel bomb sent to the Greek embassy in Rome.
Police said that a second suspect parcel, sent to the Venezuelan embassy, turned out to contain no explosives.
Greek ambassador Michael Campanis said the package arrived in the embassy on 24 December.
Two similar parcel bombs were sent to two other embassies in Rome last week. An Italian anarchist group claimed responsibility for sending those packages, which exploded, injuring two embassy employees.
Italian police warned all diplomatic missions in Rome to be on the alert for suspicious packages after the bombs exploded at the Chilean and Swiss embassies on Thursday.
Last month, Greek anarchists sent similar parcel bombs to embassies in Athens, as well as to several European leaders.
