A few hours after the police in Cagliari announced the arrests, Jesuit Father Federico Lombardi, Vatican spokesman, said the planned attack on the Vatican was "a hypothesis going back to 2010, one which did not take place."
The threat did not appear to be ongoing, he said, therefore it was not "a reason for particular concern."
DIGOS, the Italian police division that investigates terrorism and organized crime, arrested eight Pakistanis and an Afghani in seven Italian provinces April 24. They were still looking for three more suspects.
Mauro Mura, chief prosecutor in Cagliari, told reporters that DIGOS agents had arrested the spiritual leader of the terrorist cell, which was believed to have ties to al-Qaida.
The Italian investigation dates to 2005 and included telephone wiretaps of conversations that led to the theory of a plan in 2010 to strike the Vatican using a suicide bomber from Pakistan. The man apparently is no longer in Italy.