Italy has raised its security level in the wake of the Paris attacks.
Across Rome, Milan and other cities, dozens more police and army patrols have been carried out as authorities hunt for five people suspected of planning unspecified atrocities.
It comes after the US Federal Bureau of Investigation warned of potential militant strikes at major tourist destinations such as La Scala theatre in Milan or St. Peter’s Basilica in Rome. Synagogues, restaurants and hotels in the country’s two main cities could also be targets.
Italy has raised its security alert level to 2, the highest possible in the absence of a direct attack.
There were two bomb alerts on the Rome metro on Thursday but there has been no suggestion from authorities that the warning received from the United States contained plans for a specific attack.