The first Jewish rabbi to attend a Synod of Roman Catholic bishops in Rome has used the occasion to to oppose plans to put Pope Pius XII, the controversial wartime pontiff, on the road to sainthood by beatifying him.

Contradicting recent statements by Pope Benedict XVI, Shear-Yashuv Cohen, the Chief Rabbi of Haifa, said Pius XII's "silence on the Holocaust" could not be forgotten or forgiven. He added: "He should not be seen as a model and he should not be beatified, because he did not raise his voice against the Holocaust. He did not speak, either because he was afraid or for other personal reasons".

He added: "He may have helped in secrecy many of the victims and many of the refugees, but the question is - could he have raised his voice, and would it have helped or not? We, as the victims, feel the answer is yes, and I am not empowered by the families of the millions of those who died to say we forget, we forgive."

However Rabbi Cohen made his remarks to journalists at the Vatican in the margins of the three week Synod, and did not refer to Pius XII in his formal address. Instead he spoke on the meaning of the Torah for Jews, and said his presence was a "signal of hope for generations to come " after a history of "blood and tears" between Christians and Jews.

The beatification cause for Pius XII was opened in 1967, but has been opposed by critics of the Pope's behaviour towards Nazi Germany not only as pontiff but previously as Secretary of State and as papal nuncio (ambassador) to Berlin. Last month (September) Pope Benedict, who is to commemorate the fiftieth anniversary of Pius XII's death on Thursday, insisted that Pius had "spared no effort" to save Jews from Nazi and Fascist extermination.

Riccardo Di Segni, the Chief Rabbi of Rome, said many Jews in Rome felt that Rabbi Cohen "should have consulted with the local community to understand the complex relations with the Church before agreeing to take part in the synod." Rome Jews who had opposed his presence at the synod were not "extremists" but "simply people who are aware of the delicate relationship between the Church and the Jews", Rabbi Di Segni told the Jerusalem Post.

In his speech to the Synod Rabbi Cohen indirectly condemned remarks by President Mahmoud Ahmadinejad of Iran on the destruction of the Jewish state. He said Israelis felt "deep shock at the terrible and vicious words of the president of a certain state in the Middle East" during the recent UN General Assembly.

In his UN speech, Ahmadinejad said Israel "is on a definite slope to collapse, and there is no way for it to get out of the cesspool created by itself and its supporters", though he did not repeat his previous comments that Israel should be "wiped off the map."

Cohen told the bishops: "The false and malicious accusations, the threats and anti-Semitic incitement have brought back to us the painful memory of the tragedy of our people, the victims of the Holocaust. We hope for your help as religious leaders in protecting, defending and saving Israel from the hands of its enemies."

Monsignor Marc Ouellet, the Archbishop of Quebec, who is the synod rapporteur, said that "bearing in mind the tragic history of the relations between Israel and the Church", Catholics had a duty to repair any injustice committed against the Jews". He said Christian dialogue with Muslims was also "more important than ever in today's circumstances."