Ahmadinejad, who has sparked international outcry by referring to the systematic murder of six million Jews in World War II as a "myth" and calling for Israel to be "wiped off the map", launched another verbal attack on Israel.
"Thanks to people's wishes and God's will the trend for the existence of the Zionist regime is [headed] downwards and this is what God has promised and what all nations want," he said.

"Just as the Soviet Union was wiped out and today does not exist, so will the Zionist regime soon be wiped out," he added.

His words received warm applause from delegates at the Holocaust conference, who included ultra-Orthodox anti-Zionist Jews and European and American writers who argue the Holocaust was either fabricated or exaggerated.

The White House on Tuesday condemned the gathering of Holocaust deniers in Tehran as "an affront to the entire civilized world as well as to the traditional Iranian values of tolerance and respect."

A statement from White House Press Secretary Tony Snow noted the meeting coincided with International Human Rights Week, which renews the pledges of the Universal Declaration of Human Rights drafted in the wake of World War II atrocities.

"The Iranian regime perversely seeks to call the historical fact of those atrocities into question and provide a platform for hatred," Snow said.

He said the United States will continue to support those in Iran and elsewhere who seek to promote human rights "and will stand with them in their efforts to overcome oppression, injustice and tyranny."

On Monday the U.S. State Department dismissed the conference as "just awful."

Participants at the conference praised Iran's hard-line president Tuesday, saying the gathering gave them the opportunity to air theories that cast doubt on the Nazis' attempt to eradicate the Jewish people, something that is banned in parts of Europe.

The government-sponsored conference in Tehran, which has drawn Holocaust deniers from around the world, has continued to be the focus of international condemnation.

British Prime Minister Tony Blair called the conference "shocking beyond belief" and branded it "a symbol of sectarianism and hatred."

He said he saw little hope of engaging Iran in constructive action in the Middle East, saying, "I look around the region at the moment, and everything Iran is doing is negative."

Ahmadinejad initiated the two-day gathering in an attempt to bolster his image as a leader standing up to Israel, Europe and the U.S. - an image he has used to whip up support at home and abroad.

"Ahmadinejad's Holocaust comment opened a new window in international relations on this issue. Twenty years ago, it was not possible to talk about the Holocaust and any scientific study was subject to punishment. This taboo has been broken, thanks to Mr. Ahmadinejad's initiative," Georges Theil of France told conference delegates on Tuesday.

Theil was convicted earlier this year in France for "contesting the truth of crimes against humanity" after he said the Nazis never used poison gas against Jews.

Michele Renouf, an Australian socialite supporter of "Holocaust skeptics," called Ahmadinejad "a hero" for opening a debate about the Holocaust. Renouf, a blonde former beauty queen, addressed the audience wearing a green robe and Islamic headscarf, abiding by Iranian law requiring women to cover their hair.

The 67 participants from 30 countries - who include some of Europe's most prominent Holocaust deniers - were expected to meet Ahmadinejad later Tuesday.

"This conference has an incredible impact on Holocaust studies all over the world," said American David Duke, a former Ku Klux Klan leader and former state representative in Louisiana.

"The Holocaust is the device used as the pillar of Zionist imperialism, Zionist aggression, Zionist terror and Zionist murder," Duke told The Associated Press.

In Germany, Austria and France, it is illegal to deny the Holocaust or question some aspects of it, and several of the Tehran conference participants have been prosecuted. They and the conference organizers have touted the gathering as an expression of academic free speech.

Participants milled around a model of the Auschwitz concentration camp brought by one speaker, Australian Frederick Toben, who uses the mock-up in lectures contending that the camp was too small to kill mass numbers of Jews. More than 1 million people are estimated to have been killed there.

Toben, who was jailed in Germany in 1999 for questioning the Holocaust, has toured Iranian universities in the past, delivering lectures.

Also among the participants are two rabbis and four other members of the group Jews United Against Zionism, who were dressed in the traditional long black coats and black hats of ultra-Orthodox Jews. Members of the delegation, representatives of the Neturei Karta group, say the existence of the state of Israel violates Jewish law and argues that the Holocaust should not be used to justify its founding.

Many of the speakers at the conference insisted the extent of the Holocaust had been largely exaggerated, some contending Jews had exploited it to win backing for the creation of Israel.

In response to the forum, the Vatican issued a statement calling the Holocaust an "immense tragedy before which we cannot remain indifferent ... The memory of those horrible events must remain as a warning for people's consciences."

German Chancellor Angela Merkel said, "we reject with all our strength the conference taking place in Iran about the supposed nonexistence of the Holocaust."

"We absolutely reject this; Germany will never accept this and will act against it with all the means that we have," Merkel said at a news conference alongside visiting Israeli Prime Minister Ehud Olmert.

The gathering coincided with an independently convened academic conference on the Holocaust in Berlin, Germany, where historians affirmed the accuracy of the Nazi genocide data and questioned the motives of those behind the Tehran forum.