Pope Benedict, right, is seen with German Chancellor Angela Merkel at the Munich Residence in September 2006. Merkel is calling on the Pope to make a 'very clear' rejection of Holocaust denial after he rehabilitated a bishop who questioned its existence. (Frank Augstein/Associated Press)

German Chancellor Angela Merkel called on Pope Benedict XVI to make a "very clear" rejection of Holocaust denials after a former bishop was rehabilitated by the Vatican.

Her rare and public demand came amid increasing outrage among Germany's Roman Catholic leaders over Pope Benedict's decision to lift the excommunication of British-born Richard Williamson, who questioned whether six million Jews were gassed during the Nazi Holocaust.

Merkel said she "does not believe" there has been adequate clarification of the Vatican's position on the Holocaust amid the firestorm of controversy that broke out after Williamson's rehabilitation.

Benedict last week expressed "full and indisputable solidarity" with Jews and warned against any denial of the horror of the Holocaust, but several leading German bishops have decried the German-born Pope's decision and called for Williamson's rehabilitation to be revoked.

"I do not believe that sufficient clarification has been made," Merkel said.

The Vatican moved quickly to counter Merkel's suggestion.

"The Pope's thinking on the subject of the Holocaust has been expressed very clearly," said Vatican spokesman Rev. Federico Lombardi.

He cited Benedict's visit to a synagogue during his first visit to Germany as pope in 2005, a visit to Auschwitz in 2006 and his remarks during last week's general audience.

'Unequivocal words'

Lombardi quoted from what he called the Pope's "unequivocal words" at that public audience. "I hope that the memory of the Shoah leads humanity to reflect on the unpredictable power of evil when it conquers the heart of men," he quoted the Pope as saying.

"May the Shoah be a warning for all against oblivion, against denial or reductionism."

Lombardi said that during the audience "the Pope himself clearly explained the purpose of lifting the excommunication, which has nothing to do with any legitimization of positions denying the Holocaust, which were clearly condemned" by Benedict.

The issue is particularly sensitive in Germany, where denial of the Holocaust is a crime and Roman Catholic leaders have worked hard to restore relations with the Jewish community.

Williamson was consecrated by the late ultraconservative Archbishop Marcel Lefebvre without papal consent. The Holy See has said that removing the excommunication did not imply the Vatican shared his views.

Williamson, in an interview broadcast last month on Swedish state TV, said that historical evidence "is hugely against six million Jews having been deliberately gassed in gas chambers as a deliberate policy of Adolf Hitler."

He cited what he called the estimates of the "most serious" revisionists that "between 200,000 and 300,000 perished in Nazi concentration camps, but not one of them by gassing in a gas chamber."