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 wires sticking out.
Bomb disposal experts are on the scene investigating the incident. 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.
Mr Doria has received a number of threats since being appointed to his current role two years ago.
Il Messaggero reports he was targeted after finding “many irregularities”.
Describing the campaign of intimidation, they quote Mr Doria as stating: “They opened the car and rummaged through my papers, left a .38 caliber bullet with a cross-cut tip in the car.
“They tried to set my house on fire by placing primers here and there in the garden.
Aaron Ramsey and Connor Roberts scored in front of 30,000 fans in Baku, most of whom were supporting Turkey.
On Saturday Wales drew 1-1 with Switzerland, meaning they now have a decent chance of making it out of their group.
Italy thrashed Turkey 3-0 in the opening Euro 2020 match.
As society begins reopening from coronavirus lockdown authorities are warning of the terror threat from both Islamist and far-right groups.
The Metropolitan Police reported it has foiled four late-stage terror plots since the pandemic began.
Deputy assistant constable Matt Twist commented: “While the rest of us have been focused on protecting ourselves and our families from Covid-19, terrorists have not stopped planning attacks or radicalizing vulnerable people online.
“Now that we’re easing out of lockdown towards normality, we once again need the public’s help in tackling terrorism in all its forms.
“Covid-19 has driven huge numbers of people to spend increased time online.
“And we have seen an increased body of online extremism and hatred, much of which sits below the criminal threshold but which creates a worryingly permissive environment that makes it easier for terrorists to peddle their brand of hatred.”