Rome, January 29 - Italian President Giorgio Napolitano said on Tuesday that the State will give a "tough response" to Neo-Nazism, adding that "racist, anti-Jewish ideological junk" was circulating in Italy. He added that the authorities must keep their guard high because "in Italy aberrant propaganda in many cities translates into violent acts and subversive protests by organised groups". He also said, however, that in Italy there was "awareness of the aberration introduced by Fascism with anti-Semitism and the shame of the 1938 racial laws". The head of State was speaking at a ceremony at the presidential palace in Rome for Holocaust Remembrance Day, which took place on Sunday. Ex-premier Silvio Berlusconi caused controversy at another Holocaust Memorial event on Sunday, when he said the anti-Jewish racial laws of 1938 were the "worst fault" of Benito Mussolini, while adding that the Fascist dictator "did well" in many other ways. According to organizers of the event, which was sponsored by the Milan Holocaust Memorial Foundation, Berlusconi had shown up uninvited. He then dozed off during the ceremony. In his sprawling speech Tuesday, Napolitano warned against "persistent instances of revisionism and denial," stressing Italy's close support of Israel and linking anti-Semitism to Islamic fundamentalism. According to the Milan-based Observatory for Antisemitic Prejudice, anti-Semitic episodes such as graffiti and online attacks were up 40% in 2012. On Monday a black swastika was found on a Partisan memorial plaque in Turin which police believe was painted on Sunday, Holocaust Remembrance Day. Last week a group of 10 right-wing extremists were arrested in Naples and other cities for allegedly organizing street brawls, attacking a leftist clubhouse with Molotov cocktails and recruiting young militants to their anti-Semitic cause. Police wiretaps during the investigation revealed group readings of Adolf Hitler's Mein Kampf.