Pope Benedict XVI on Monday paid tribute to the memory of six million Jews who perished in the Holocaust, pledging to work tirelessly to prevent such hatred from recurring in the hearts of mankind again. But the pontiff's closely-watched speech at Jerusalem's Yad Vashem Holocaust Memorial stopped short of an apology on behalf of the Catholic Church, producing palpable disappointment among those Israelis who had expected a historic address from the German-born pope on the first day of his visit here. "We're talking about the pope, who is also a representative of the Holy See, which has a lot to ask forgiveness from our people for," Knesset Speaker Reuven Rivlin said during an interview on Israel Radio on Tuesday. "And he is also a German, whose country and people have asked forgiveness. But he himself comes and speaks to us like a historian, as an observer, as a man who expresses his opinion about things that should never happen, and he was - what can you do? - a part of them." "If we let this go, in the end they'll say, 'the Jewish people can manage,'" the Knesset speaker said. Rivlin added during the interview that "there is one thing which is forbidden to forget, and we must not allow ourselves to forget it, not even in the act of giving up on it in one way or another due to protocol. The Holocaust is not protocol." After the pope's speech, the Knesset speaker - who was absent from all of the welcoming festivities other than the visit to Yad Vashem - said that "everything that we feared came to fruition." "I came to the memorial not only to hear historical descriptions or about the established fact of the Holocaust. I came as a Jew, hoping to hear an apology and a request for forgiveness from those who caused our tragedy, and among them, the Germans and the church. But to my sadness, I did not hear any such thing," he said. "The visit to Yad Vashem does not constitute an expression of regret as such," added Rivlin. "The eyes of Jews across the world, and of the nation in Israel, were directed here, in anticipation of hearing honest communion - personal and determined - regarding the Holocaust of their people. And we heard nothing of the sort." Benedict had said during Monday's speech that "I have come to stand in silence before the monument erected to honor the millions of Jews killed in the horrific tragedy of the Shoah." "They lost their lives, but they will never lose their names. These are indelibly etched in the hearts of their loved ones, their surviving fellow prisoners, and all those determined never to allow such an atrocity to disgrace mankind again." The solemn memorial service, which was held at the Holocaust Memorial's darkened Hall of Remembrance, was seen as the highlight of the pontiff's visit to the Jewish state, especially in light of the recent controversy over the pope's decision to revoke the excommunication of a bishop who denies the Holocaust. "I reaffirm - like my predecessors - that the church is committed to praying and working tirelessly to ensure that hatred will never reign in the hearts of men again," he said. The English-language address by the pontiff, which was peppered with biblical quotations but which never referred to the Nazis and avoided all Holocaust-related issues of contention, was preceded by the pope's rekindling of the eternal flame in the chamber, which has a mosaic floor engraved with the names of 22 of the most infamous Nazi murder sites. He also laid a wreath over a stone crypt containing the ashes of Holocaust victims. "As we stand here in silence, their cry still echoes in our hearts. It is a cry raised against every act of injustice and violence. It is a perpetual reproach against the spilling of innocent blood," he said. "I am deeply grateful to God and to you for the opportunity to stand here in silence: a silence to remember, a silence to pray, a silence to hope," he concluded. The chairman of the Yad Vashem Council, Rabbi Yisrael Meir Lau, who is a Holocaust survivor, expressed disappointment at the pope's speech, saying that "there certainly was no apology expressed here." "Something was missing. There was no mention of the Germans or the Nazis who participated in the butchery, nor a word of regret," Lau said. "If not an apology, then an expression of remorse." Yad Vashem chairman Avner Shalev said that the "certain restraint" in the formulation of the speech was a "missed opportunity." "I did not expect an apology, but we expected more," he told The Jerusalem Post. "This is certainly no historic landmark." "I had expected a historic speech from the German pope at the site which is a memorial altar for the victims of Nazi Germany," said Prof. Shevah Weiss, a former Yad Vashem chairman and Holocaust survivor. "And though the speech was moving - it wasn't that." Others said that too much focus should not be put on the one speech. "His very presence at Yad Vashem is a statement, particularly against those Holocaust deniers who challenge the history of the Shoah," said Rabbi Arthur Schneier, senior rabbi of Park East Synagogue in New York, who hosted the pope last year and was here for the papal visit. The august ceremony, which included a brief encounter between the pope and six Holocaust survivors as well as a Righteous Among the Nations, concluded with the pope signing the guest book and the singing of "Hatikva." "His mercies are not spent," the pope wrote, quoting from the Book of Lamentations. The pope arrived at Ben-Gurion Airport late Monday morning and was welcomed by President Shimon Peres and Prime Minister Binyamin Netanyahu. After the greetings, the pope flew by helicopter to Jerusalem, where he was met by Mayor Nir Barkat and scores of flag-waving Jewish, Christian and Muslim children. "You will feel at home because you, too, Your Holiness, are a shareholder of this great city," Barkat told the pope, in a brief welcoming ceremony at the city's Mount Scopus tarmac. Later, at Beit Hanassi, Peres and Benedict planted an olive tree together. Rebecca Anna Stoil contributed to this report.