Vatican City  - The Vatican's newspaper on Monday described as "unacceptable" remarks made by a Roman Catholic bishop in which he denied that millions of Jews were killed in Nazi gas chambers.

The Osservatore Romano referred to the row over Saturday's announcement that Pope Benedict XVI had revoked the 1988 excommunication of four ultra-traditionalist bishops belonging to the Society of Pius X (SSPX) - a group which broke with the Vatican over reforms ushered in by the Second Vatican Council in the 1960s.

Among the reinstated clerics is British-born Richard Williamson, who in an interview broadcast on Swedish television last week said that "historical evidence" contradicted the widely accepted figure of some six million Jews being murdered by the Nazis during World War II.

In an apparent move to placate those Jews as well as many Catholics and others who have reacted angrily to Benedict's reinstatement of Williamson, Osservatore Romano specified that the four bishops' "full communion" with the Church was still contingent on them espousing the Vatican's views on relations with other faiths.

Such relations, the article in the Vatican newspaper noted, were specified by the Second Vatican Council through which hateful attitudes towards Jews were declared sinful.

"From the acceptance of the Council there stems the necessity for a clear position on Holocaust denial," L'Osservatore Romano said.

Quoting the declaration, it noted how Catholic teaching "deplores the hatred and persecutions aimed at the Jewish people throughout the ages and those who commit such acts."

Recent popes, including Benedict have made this teaching explicit and "not a matter of opinion" for individual Catholics, the article said.

Without referring to Williamson by name, the article noted how "the recent (Holocaust) denial remarks contradict this teaching and are as serious as they are regrettable."

Meanwhile Benedict's homeland Germany, Williamson faces an inquiry over his remarks.

Though broadcast in Sweden, they were made to a television interviewer as he visited an SSPX seminary in the German city of Regensburg.

Denying the Holocaust is treated in German law as a crime.

On Saturday the Vatican's chief spokesman said the Vatican completely rejected Williamson's remarks about the Holocaust, but that they had nothing to do with his 1988 excommunication.

The SSPX's chief quarrel with the Vatican has revolved around the Second Vatican Council's replacing the Latin Mass liturgy with ones in local languages.

The Vatican estimates that SSPX has around 600,000 members in the world in which 1.1 billion people are described as Roman Catholics. dpa