NEW YORK - A top United Nations official skipped a Holocaust remembrance ceremony Tuesday after American Jewish groups and Israeli diplomats objected to his participation. A spokesman for Miguel d'Escoto Brockmann, the president of the UN General Assembly, had said the Nicaraguan diplomat - who has drawn fire for calling on the international community to boycott Israel over Gaza and for embracing Iranian President Mahmoud Ahmadinejad - would attend. Instead of walking out, dozens of Holocaust survivors and American Jews clapped politely as the Rwandan ambassador read a statement on d'Escoto's behalf and then eagerly waved crackling plastic Israeli flags to welcome Israeli Ambassador Gabriela Shalev. Israel's envoy quietly recounted the story of her grandparents' death at Auschwitz - and then took aim not just at Holocaust deniers but at those who fail to condemn them. "We have the responsibility not to remain silent for to remain silent and indifferent to the horrors of the Holocaust is probably the greatest sin of all, let alone denying it," Shalev said. "We have the responsibility to condemn any member state of the United Nations that calls for the destruction of another member state and engages in Holocaust denial," she said, a reference to d'Escoto's refusal to condemn Ahmadinejad for his comparison of Israel to a "cesspool" from a UN podium last fall or for earlier statements that Israel should be "wiped off the map." Earlier in the day, an Iranian government spokesman accused Israel of making up the Holocaust in order to justify its existence, according to Agence France Presse. "The Holocaust is a concept coming from a big lie in order to settle a rootless regime in the heart of the Islamic world," the wire service reported Gholam Hossein Elham told a conference on Gaza in central Iran's religious city of Qom, citing the state IRNA news agency. A spokesman for d'Escoto said the diplomat "had to travel urgently" and had not returned to New York in time for the commemoration, which featured a survivor from Transnistria as well as a Soviet World War II veteran, a piano performance and a cantorial recitation of "Ani Ma'amin." In his statement, d'Escoto warned against repeating the logic of Nazi propaganda campaigns that "aimed to convince ordinary Germans, Poles and so many others that their problems were a consequence of the presence of others in their countries - Roma, communists, gays and lesbians, and most of all, Jews." "We must educate our youth about the values that virtually every religious and ethical tradition share in common - the fact that we are all brothers and sisters and must demand respect for the 'others' who live amongst 'us,'" he added. In Europe, survivors and government officials marked the 64th anniversary of the day the advancing Soviet army liberated Auschwitz in 1945. Bronislawa Horowitz-Karakulska, 78, credited her survival to destiny - and to Oskar Schindler, the German industrialist whose story was told in Steven Spielberg's "Schindler's List." He shielded more than 1,000 Jews from Nazi death camps by hiring them to work in his factories. "The fact that I am alive - for this I thank Oskar Schindler and the fact that he was able to get me and 300 women out of here and get us to the camp in Brunnlitz," Horowitz-Karakulska said, speaking in a school gymnasium to a group of local high-school students. More than 1 million people, mostly Jews, died in Auschwitz's gas chambers or through forced labor, disease or starvation. Another survivor, Tadeusz Sobolewicz, 85, accused Germany's younger generations of forgetting about the horrors their country inflicted, and misrepresenting history by playing up their own suffering. "The columns of many Western newspapers are full of information about the sufferings of the German people, the underground struggle against Hitler, the assassination attempts against him, and so on," he said. In a speech in Germany's lower house of parliament, President Horst Koehler praised young Germans' efforts to learn about their nation's history and honor the victims of the Holocaust. "Responsibility for the Shoah is part of the German identity," Koehler told members of parliament. The country's main Jewish group, however, boycotted the ceremony, saying they were snubbed by not being officially greeted by the speakers at the event. In Warsaw, an antique tram car topped with the Jewish Star of David trundled through neighborhoods in what was once the Jewish ghetto of Nazi-occupied Warsaw. The tram traveled empty through the now-bustling streets of the Polish capital to symbolize the absence of those who perished in the Holocaust. Italian lawmakers in Rome observed a minute of silence, and Premier Silvio Berlusconi, who heads a conservative bloc that includes former neo-fascists, urged teachers and students to treasure and mark the anniversary "so that Remembrance Day can teach to everyone the value of peace and peaceful coexistence among peoples." AP contributed to this report.