The suspect device was found in the Mazzini square and is being investigated.
Authorities were first alerted to the danger at shortly before 6pm local time.
Italian publication Il Messaggero reports police sources as saying the device was homemade.
It consisted of a cylinder of gunpowder, with shrapnel embedded and electric vires sticking out.
According to Il Messaggero the device was designed so it “could have exploded”.
Adnkronos reports the suspect package was found by a car belonging to Marco Doria, president of park and historic villa redevelopment in Rome.
More to follow…