Five Italian right-wing extremists thought to belong to the Fascist "Militia" movement were arrested in Rome on Wednestoday while eight others were placed under investigation, police said.

Those arrested are accused of inciting racial hatred, praising Fascism and threatening institutions and representatives, including Rome's Jewish and Roma communities, both parliament speakers and the city's mayor, they said.

Two of the militants are also accused of having planned "to use explosives to hit targets" such as Riccardo Pacifici, the head of Rome's Jewish community -- though the attacks were never attempted.

All five are charged with having spread ideas based on ethnic and racial hatred by means of a bimonthly magazine called "Insurrection," as well as through offensive graffiti on the eternal city's ancient walls.

One of those still under investigation is a 16-year-old minor, police said.