World leaders are condemning Iran's government-sponsored conference of those who question whether Nazi Germany exterminated six million Jews during World War II.
A White House spokeswoman in Washington called the Holocaust conference an affront to the civilized world and to Iran's tradition of tolerance.
The Vatican called the Holocaust an "immense tragedy" to which one cannot be indifferent.
British Prime Minister Tony Blair called the conference "shocking beyond belief."
The European Union's top justice official, Franco Frattini, condemned what he called an attempt to deny and trivialize the Holocaust.
Iran's President Mahmoud Ahmadinejad told the Tehran conference Tuesday that Israel is in decline and will soon disappear.
The two-day conference opened Monday.
German Chancellor Angela Merkel also condemned the conference. She met in Germany today with Israel's Prime Minister Ehud Olmert, who called the conference "sickening."
Iranian Foreign Minister Manouchehr Mottaki said Monday that the event is not aimed at confirming or denying the Holocaust. He said the conference is an opportunity to debate it.
A former American politician and member of the white supremacist Ku Klux Klan, David Duke, is attending. So is French Professor Robert Faurisson, who denies the existence of the gas chambers used to exterminate the Jews.