Appeal to help Rome combat terrorist threat.

Rome's commissioner Franco Gabrielli has urged Rome residents to report illegal Bed and Breakfasts in the capital as part of increased security measures during the upcoming Holy Jubilee year.

Authorities view the unregistered guests at illegal B&Bs as a potential weak point in their plan to secure the city from the threat of terrorism in the wake of the recent Paris attacks.

Gabrielli is appealing to Romans' "civic duty" to report the offending B&Bs who will host an estimated 30,000 "invisible guests" during the Jubilee, which runs from 8 December until 20 November next year.

Gabrielli's appeal comes days after the capital's police chief Nicolò D’Angelo announced heightened security on public transport and at tourist sites.