(CNN) -- Palestinian Authority President Mahmoud Abbas called the Holocaust the most heinous crime in modern human history, his office said in a statement Sunday.
He called the Holocaust an embodiment of racism, in response to a question by Rabbi Marc Schneier on the eve of Holocaust Remembrance Day, the statement from the Palestine Liberation Organization said. He said Palestinians reject racism and ethnic discrimination, and he called on the world to fight it.
"The Palestinian people, who suffer from injustice, oppression and denied freedom and peace, are the first to demand to lift the injustice and racism that befell other peoples subjected to such crimes," the statement read.
The PLO called on Israel to "conclude a just and comprehensive peace in the region, based on the two states vision."
Monday is Holocaust Remembrance Day. Ceremonies begin after sundown Sunday.
In his 1983 doctoral dissertation, Abbas wrote of "the Zionist fantasy, the fantastic lie that six million Jews were killed" and said only 890,000 Jews were killed by Nazis -- and that these were chiefly the victims of a Zionist-Nazi plot, the Jerusalem Post reported Sunday. But in 2011, he said he did "not deny the Holocaust" and that he had "heard from the Israelis that there were six million" victims, adding, "I can accept that," The New York Times reported.
Israeli Prime Minister Benjamin Netanyahu told CNN's "State of the Union" on Sunday that he was struggling to reconcile Abbas' remarks on the Holocaust with the decision by his Fatah movement last week to seek a unity government with Hamas.
Abbas "can't have it both ways," by calling the Holocaust the most heinous crime in modern history while embracing Hamas, a "terrorist organization that denies the Holocaust and openly calls for a new extermination of the six million Jews of Israel," Netanyahu said.
Netanyahu said Abbas is likely seeking to carry out "damage control" with his latest remarks.
"What he's trying to do is to placate Western public opinion that understands that he delivered a terrible blow to the peace process by embracing these Hamas terrorists, and I think he is trying to wiggle his way out of it."
A tweet Sunday from Netanyahu's office said Abbas "is forging a pact with Holocaust deniers." It included a photo of Abbas smiling alongside Hamas leader Khaled Mashaal.
Fatah and Hamas announced Wednesday they will begin discussions to form a unity government. An interim government could be finalized in the next five weeks, with elections possible by early 2015, Fatah spokesman Fayez Abu Eita said.
After the reconciliation was announced, Netanyahu's office said Israel canceled peace negotiations that were scheduled to take place that night.
Israel and the Palestinian Authority face an April 29 deadline to agree on a framework for a comprehensive peace treaty, but the sides appear far apart.