A reporter from online newspaper Fanpage infiltrated Gioventu Nazionale, Meloni's rightist Brothers of Italy youth movement, and recorded videos in which members declared themselves fascists and shouted the Nazi slogan "Sieg Heil".

The investigation also showed a Gioventu Nazionale member mocking Brothers of Italy senator Ester Mieli for her Jewish origin, and revealed chats on messaging platforms where militants took aim at ethnic minorities.

Fanpage has broadcast its expose in two instalments, the second one on Wednesday.

"The Jewish Community of Rome condemns the shameful images of racism and antisemitism that emerged from the Fanpage investigation," the group's President Victor Fadlun wrote on his X social media account on Thursday.

Fadlun offered his support to senator Mieli and urged Brothers of Italy to take "appropriate action," saying it was "imperative that society and institutions" strongly react against hatred and discrimination.

Brothers of Italy said the youth group members had used "unacceptable" language "incompatible with the values" of the party and it vowed to punish those responsible. However, it criticised the way the images were captured because the reporter was undercover.

Italian newspaper la Repubblica reported on Thursday that two of the members involved in the investigation had resigned from their posts.

Brothers of Italy traces its roots to the Italian Social Movement (MSI), formed in 1946 as a direct heir of Benito Mussolini's fascist movement that ruled Italy for more than 20 years.

Meloni has repeatedly condemned the racist, anti-Jewish laws enacted by the dictator in 1938 and has tried to turn her party into a mainstream conservative force.

But she has ignored many calls for her to declare herself "anti-fascist" and her critics say she has so far failed to fully mark a distance with neo-fascism.

Senate Speaker Ignazio La Russa, a founding member of Brothers of Italy, used to show off his collection of Mussolini memorabilia as recently as 2018.