Cardinal Pietro Parolin said recently the Vatican was considering whether to ramp up security.
He said: “The Vatican could be a target because of its religious significance.
“We are capable of increasing the level of security in the Vatican and the surrounding area.
“But we will not let ourselves be paralysed by fear.”
Rome has been the subject of a number of threatening terror films released by the extremists in recent weeks.
It is thought the focus on Rome, and specifically the Vatican City, may be in response to the Pope’s recent condemnation of the deadly terror attacks in Paris, as well as its status of the capital of the Catholic world.
St Peter’s Basilica in the video, bathed in an eerie orange light
“There are no justifications for these things.”
The latest, and most ominous video, shows CGI ISIS tanks advancing on a crumbling Colosseum, promises a final battle between “believers” and “crusaders.”
It also shows an eerie St Peter’s Basilica, the papal enclave within the Vatican City, bathed in an orange light and accompanied by chilling music.
The video’s narrator then apparently claims that ISIS will take over Rome, destroying crucifixes and taking Christian women as slaves.
In it, a jihadi vowed: “By Allah, if we brought down France in its homeland, in Paris, then we swear, by the command of Allah, we will attack America in its heartland, in Washington, Allah permitting, and we will invade Rome, Allah permitting.”
Pope Francis, who it is feared may be next on ISIS’s terror hit list
He said: “The Holy Father does not intend to abandon the style of his pontificate, which is based on proximity, that is, on a direct encounter with the greatest number of people possible.
“Even as pontiff, he has remained a priest who does not want to lose contact with his flock.
“Those of us entrusted with his security must adapt to his style and not the other way around.
“We must do everything possible so that he can continue to carry out his ministry as he wants and believes is best.”