Sirens pierced the air in a mournful two-minute wail heard throughout Israel on Thursday, in tribute to the six million Jews murdered by the Nazis, as the country marked its annual Holocaust Remembrance Day. In an annual ritual, drivers switched off their engines and people put aside their daily activities to stand in silence as the sirens sounded. The official state wreath-laying ceremony took place at the Warsaw Ghetto uprising memorial at Yad Vashem just after the siren was sounded, in the presence of Prime Minister Ehud Olmert and other VIPs. The "Unto Every Person There is a Name" ceremony followed - in which Holocaust victims' names were read out - at both the Hall of Remembrance at Yad Vashem and the Knesset. On Wednesday, President Shimon Peres said 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 Adolf Hitler had it acted in time. In his address, Peres urged state leaders to stop the eruption of a global war before it begins, 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 occur again," Peres said. The country's senior 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 creation of the State Israel of its legitimacy 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 have believed that the ugly head of Jew hatred and Israel hatred would still be 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.