Benito Mussolini was a fierce anti-Semite, who proudly said that his hatred for Jews preceded Adolf Hitler's and vowed to "destroy them all," according to previously unpublished diaries by the Fascist dictator's longtime mistress. Excerpts were published Monday. According to the diaries, Mussolini also talked about the warm reception he received from Hitler at the 1938 Munich conference - he called the German leader a "softy" - and attacked Pope Pius XI for his criticism of Nazism and Fascism. On a more intimate note, Mussolini was explicit about his sexual appetites for his mistress and said he regretted having affairs with several other women. The dairies kept by Claretta Petacci, Mussolini's mistress, between 1932 and 1938 are the subject of a book coming out this week entitled "Secret Mussolini." Excerpts were published Monday by Italy's leading daily Corriere della Sera and confirmed by publisher Rizzoli. Historians said the diaries appeared to be convincing and reinforced the image that Mussolini was strongly anti-Semitic, even though early on there was some Jewish support for his Fascist movement. But they cautioned that these are the diaries of the dictator's lover - not Mussolini himself - and therefore must be taken with an extra grain of salt. Corriere said the diaries shed new light on Mussolini, who had been seen as more obsequious toward the pope and "dubious" over Italy's racial laws, which led to widespread persecution of Italian Jews. Many of the excerpts that were published date to 1938, a crucial year during which Mussolini's Fascist regime passed the racial laws and Europe sealed its appeasement toward Nazi Germany at the Munich conference. "I have been a racist since 1921. I don't know how they can think I'm imitating Hitler," Mussolini is quoted as boasting in August 1938. "We must give Italians a sense of race." Italy's racial laws restricted the rights of Jews and expelled them from government, university and other fields. In 1943, German troops occupied northern and central Italy, and thousands of Jews were deported. According to some researchers, there were 32,000 Jews in 1943 in Italy, of whom over 8,000 were deported to Nazi concentration camps. "These disgusting Jews, I must destroy them all," Mussolini was quoted as saying by his lover in October 1938. At another point he calls them "enemies" and "reptiles," according to the excerpts. Mussolini also denounced Pius XI, who saw the rise of anti-Semitism in the last years of his 1922-39 papacy, as harming the Catholic Church. Pius commissioned an encyclical to denounce racism and the violent nationalism of Germany, but he died before releasing it and it was never published. The Fascist dictator said that "there never was a pope as harmful to religion" as Pius XI and accused him of doing "undignified things, such as saying we are similar to the Semites," according to the excerpts. For years, the Vatican has struggled to defend Pius' successor - the wartime Pope Pius XII - against claims he didn't do enough to save Jews from the Holocaust. Mussolini had kind words for Hitler, whom he said was "very nice" and had tears in his eyes when he met the Italian dictator in Munich. "Hitler is a big softy, deep down," Mussolini is quoted as telling Petacci on October 1, 1938, shortly after the conference. Mussolini also wrote to Petacci about his "mad desire" for her "little body" and his regret over having had relations with other women. "I adore you and I'm a fool. I mustn't make you suffer," he was quoted as saying. Mussolini and Petacci were shot by partisans on April 28, 1945, and their bodies were displayed to a jeering crowd hanging upside-down from a gas station in a Milan square. Piero Melograni, a historian who has written several books on Fascism and World War II, said the excerpts were "convincing in terms of the character that emerges and therefore the authenticity of the diaries." He said the diaries appear to strengthen the notion of a strongly anti-Semitic Mussolini, as demonstrated by the 1938 laws and several speeches. But he said the personal quotes almost "humanize" him. Another prominent historian, Giovanni Sabbatucci, said that while he has no reason to doubt the authenticity of the diaries, he is less sure of their historical significance because they might not reflect Mussolini's real thoughts. "We must not forget that, even when authentic, we are reading what a mistress was writing about what her lover told her," he said in a phone interview. Sabbatucci said that while there is no doubt that Mussolini had developed a strong anti-Semitism in the later years of his life, historians are split as to when these sentiments began. The diaries appear to show he developed them earlier rather than later, but Sabbatucci was doubtful. "We must not take for granted that she correctly wrote what she was told. And we must not take for granted that what she was told was the truth and not some lover talk," said Sabbatucci, who teaches contemporary history at Rome's Sapienza University.