As Israel marked the start of Holocaust Remembrance Day under the shadow of Iran's nuclear program, President Shimon Peres said Wednesday that the world must act against global threats in order to ensure that the Holocaust never happens again. "It is forbidden in history to be late," Peres said at the official state ceremony at Yad Vashem marking the opening of Holocaust Remembrance Day, noting that the world could have stopped Adolph Hitler had it acted in time. In his address, Peres urged state leaders to stop the eruption of global war before it began, in what aides said was a reference to Iran's nuclear program. "We will ask ourselves every morning what we must do in order that what was will never return again," Peres said. The country's elder statesman said that until this very day he could not grasp how the Holocaust - where one third of the Jewish people was wiped out - could have happened, and how other nations stood silently by, or worse, assisted in the mass murder, adding that if Hitler had succeeded in building nuclear weapons, the world could have been destroyed. Prime Minister Ehud Olmert blasted Holocaust deniers for trying to strip the legitimacy of the creation of the State Israel by denying the existence of the Holocaust, and said that no force in the world was stronger than the Israeli spirit. "Even 60 years later, who would believe that the ugly head of Jew hatred and Israel hatred is rearing all over the world; still inciting, poisoning and enticing." He noted that the Holocaust only emphasized the need for the establishment of the State of Israel, which belatedly rose out of the ashes of the Holocaust. "There is no force in the world stronger than the spirit of this people, that emerged from the abyss of annihilation to the summits of creation, success, building and might of the State of Israel," Olmert said. On Thursday, a two-minute siren will sound at 10 a.m. at the start of a series of day-long ceremonies throughout the nation. The official state wreath-laying ceremony will take place just after the siren is sounded Thursday at the Warsaw Ghetto uprising memorial at Yad Vashem in the presence of the prime minister and other VIPs. The "Unto Every Person There is a Name" ceremony will follow - in which Holocaust victims' names are read out - at both the Hall of Remembrance at Yad Vashem and the Knesset.