UN General Assembly President Miguel d'Escoto Brockmann on Tuesday skipped the world body's ceremony marking International Holocaust Remembrance Day, after American Jewish leaders threatened to demonstratively exit Tuesday's if he used the podium to attack Israel.

D'Escoto, who has repeatedly made virulently anti-Israel statements, was to be the event's host by virtue of his official position and was scheduled give the opening speech.

Last year, the General Assembly president likened Israel's actions in the West Bank and Gaza to "the apartheid of an earlier era," and tried to ban Israel's envoy to the UN from speaking at a ceremony to mark 60 years since the institution adopted the Universal Declaration of Human Rights.

D'Escoto did send a message to the assembly via the Rwandan envoy to the UN, whom he had asked to serve as his representative. "All genocides, all holocausts start with alienation, denominization and marginalization of others," D'Escoto was quoted as saying in his absence.

AJC Executive Director David A. Harris told Haaretz that d'Escoto had chosen not to attend the event because he knew "he did not belong" there. Harris said D'Escoto also mostly likely understood that "his presence would have insulted the event because of his viscious attacks on Israel."

Professor Gabriela Shalev, Israel's ambassador to the UN, had also threatened to quit the ceremony should d'Escoto lash out at Israel.

Several American Jewish groups, including the Conference of Presidents of Major Jewish Organizations, had earlier sought to have D'Escoto excluded from the ceremony, but to no avail.

In her speech to the assembly, Shalev said the world has the "responsibility not to remain silent" to the genocide perpetrated by the Nazis during World War II.

"We have the responsibility not to allow genocide of the Jewish people, nor of any other peoplem," she said. "We have the responsibility to learn and to teach the lessons of the Holocaust, to prevent it from ever reoccurring."

"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," she said, adding: We have the responsibility to act against the forces of anti-Semitism, bigotry, and racism in any form."

UN Chief Ban Ki-Moon, who was unable to attend the ceremony due to an engagement in Madrid, urged the international community to examine why the Holocaust was not stopped in order to prevent future genocides.

"We must continue to examine why the world failed to prevent the Holocaust and other atrocities since," Ban said in a statement. "That way we will be better armed to defeat anti-Semitism and other forms of intolerance."

Some 1,600 guests were expected to attend the event, ranging from Holocaust survivors to UN ambassadors.