Russia criticized Iran for hosting a conference that greatly diminished the Holocaust tragedy, saying Moscow opposed "the concealment of the truth about the monstrous crimes of the Nazis."

Russia had condemned Tehran and President Mahmoud Ahmadinejad in the past for threatening Israel and denying the systematic killing of 6 million Jews by the Nazis during World War II, Russia's Foreign Ministry spokesman Mikhail Kamynin said as quoted by Russian leading news agency, RIA NOVOSTI.

Russia opposes "the revision of results of humanity's most difficult struggle against Nazism," he said, adding that Russia shares "the determination of the UN general assembly not to allow the denial of the Holocaust."

IRAN CONDEMNED WORLDWIDE

International community has condemned Holocaust conference underway in Iran that questions the mere existence of Holocaust, Nazi Germany's persecution of Jews during World War II.

"A conference designed to try to deny the fact that six million innocent people lost their lives in a brutal, despicable manner is just awful," US State Department spokesperson Sean McCormack said on Monday.

Prime Minister Tony Blair said Tuesday he found it "unbelievable" and "shocking" that Iran hosted such a conference.

"I think it is such a symbol of sectarianism and hatred toward people of another religion, I find it just unbelievable," said Blair. "I found that this conference that they had questioning the Holocaust is shocking beyond belief."

Iranian government-backed two-day conference focuses on whether the mass killings during the Holocaust has been exaggerated, while raising questions about whether the Nazis actually used gas chambers to kill over 6 million Jews in World War II took place.

Prominent "revisionist" historians, including a former Ku Klux Klan leader, took part in a conference which topics include "A Challenge to the Official Holocaust Story," and "Holocaust, the Achilles Heel of a Primordial Jewish Trojan."

Iranian President Mahmoud Ahmadinejad has regularly trivialised the Holocaust by calling it a myth and called for Israel to be wiped off the map.

Israeli Prime Minister Ehud Olmert described the conference as "sickening," while German Chancellor Angela Merkel the conference's dismissals of the Holocaust "in the strongest terms."

"Coupled with the fact that this is a regime that says it wants to wipe Israel off the face of the map, (the conference) should be of grave concern to everybody around the world," U.S. State Department spokesperson said.

CONFERENCE DENIED THE EXISTENCE OF HOLOCAUST CAMPS

An estimated six million Jews died in the Holocaust. An estimated 1.5 million people died at Auschwitz concentration camp, also known under Polish name of Oswiecim, from gassing, starvation, exhaustion, beatings and disease. Such camps were an essential part of the Nazis' mass murder of Jews, political opponents, and others considered socially and racially undesirable including Jehovah's Witnesses, Gypsies, dissenting clergy, and homosexuals.

Dachau, one of the first Nazi concentration camps, opened in March 1933, and six death or extermination camps were constructed in Poland. These so-called death factories were Auschwitz-Birkenau, Treblinka, Belzec , Sobibór, Lublin (also called Majdanek ), and Chelmno.

Ultimately, the Nazis were responsible for the deaths of some 2.7 million Jews in the death camps. Starting early in 1942, the Jewish genocide (sometimes called the Judeocide) went into full operation. Auschwitz 2 (Birkenau), Treblinka, Belzec, and Sobibór began operations as death camps. There was no selection process; Jews were destroyed upon arrival.

The total figure for the Jewish genocide, including shootings and the camps, was between 5.2 and 5.8 million, roughly half of Europe's Jewish population, the highest percentage of loss of any people in the war. About 5 million other victims perished at the hands of Nazi Germany.