The Vatican on Tuesday criticised a conference being hosted by Iran questioning the Holocaust, calling the death of millions of Jews during World War II an "immense tragedy" which must never be forgotten.
"The recollection of those tragic acts must be held up as a warning to all in an effort to end all conflicts," the Vatican statement said.
"The last century saw an attempt to exterminate the Jewish people, and consequently millions of Jews of all ages and social classes were killed simply because they belonged to that people."
A conference entitled "Review of the Holocaust, Global Vision" which opened in Tehran on Monday has been widely condemned by Western leaders.
The statement recalled that a few years ago the Vatican released a document on the Holocaust which expressed "respect" and "compassion" for the tragic fate of the Jewish people during Nazism.
Earlier this year, Pope Benedict XVI condemned anti-Semitism, urging humanity never to forget the horror of Auschwitz, which he visited in May during a trip to Poland.
During a trip to Germany in August 2005, Pope Benedict made a point of visiting the synagogue in Cologne which was destroyed by the Nazis and rebuilt after the war.
He urged Christians and Jews to work together so that the world would never again witness the "insane racist ideology" which led to the Holocaust, which he described as an "unspeakable and previously unimaginable crime."
In a message marking the 60th anniversary of the liberation of Auschwitz in 2005, his predecessor pope John Paul II said the Holocaust was a "crime that will forever stain the history of humanity."
Its recollection must serve to warn mankind against ideologies that seek to "crush human dignity because of differences in race, color, language or religion."
This appeal must be heeded by all, but above all by "those who use violence and terrorism in the name of religion," the Polish pope said.
