Italian police have blocked access to a white supremacist website and arrested four people for allegedly inciting racial hatred and spreading anti-Semitism.

Authorities on Friday blocked Stormfront, a white supremacist website based in the United States, and shut down its Italian-language forum.

They also confiscated knives, batons and baseball bats as well neo-Nazi and Fascist propaganda, including pamphlets and banners emblazoned with swastikas, in searches of properties mostly in northeastern Italy.

Prosecutors in Rome launched the investigation after the group published blacklists of religious leaders, politicians, journalists and judges citing their support of immigrants. They also published lists of prominent Jewish citizens.

The four were arrested in the northern city of Milan and in Frosinone and Pescara in central Italy.