The bombing of Christian churches in Iraq combined with warnings from an Islamist terror group for Italy to withdraw troops from Iraq by Aug. 15 or face attacks has prompted authorities to increase security around religious sites. The task is daunting: Italy has identified some 13,600 sites at risk, including the Vatican and St. Peter’s Basilica, guarded by police and an additional 4,000 soldiers. Some officials believe that the threat may be a media campaign against Italy’s involvement in the occupation of Iraq, but they are taking the threats seriously.