An Italian website quoted Giacomo Babini, 81, the emeritus bishop of Grosseto, as saying he believed a "Zionist attack" was behind the criticism, considering how "powerful and refined" the criticism is.
Babini was quoted by Catholic website Pontifex as saying: "They do not want the Church, they are its natural enemies. Deep down, historically speaking, the Jews are God killers."
The Bishops' Conference on Sunday rushed to issue a statement quoting Babini denying he had ever given the interview in the first place. "Statements I have never made about our Jewish brothers have been attributed to me," he said.
According to The Guardian, the interview was spotted on Friday by the American Jewish Committee, which said Babini was using "slanderous stereotypes, which sadly evoke the worst Christian and Nazi propaganda prior to World War II."
On its website, the American Jewish Group Committee quoted another bishop, Vincenzo Paglia, as saying Babini's remarks were "entirely contrary to the official line and mainstream thought of the Catholic church".
According to The Guardian, Babini has previously been quoted on the Pontifex website accusing Jews of exploiting the Holocaust, as well as criticizing homosexuality.
The comments follow a series of statements from Catholic churchmen alleging the existence of plots to weaken the church and Pope Benedict XVI.
Last week, Pope Benedict's personal preacher apologized to Jews after he compared attacks on the Church and the pope over a sexual abuse scandal to "collective violence" against Jews throughout history.