Marking a major U-turn for under-pressure Pope Benedict XVI, the Vatican statement also said that Williamson’s remarks were "not known" to the German pontiff "at the moment of lifting the excommunication" of the Englishman and three other renegade bishops last month.

Williamson is on record as denying that the Nazis used gas chambers to eliminate millions of Jews during World War II, saying only 200,000 to 300,000 Jews were killed in concentration camps.

His remarks were made in an interview broadcast on Swedish television on Jan. 2, the day after a papal decree lifted his excommunication but two days before the pope’s decision was made public.

Growing pressure from Jewish and Catholic organizations turned overtly political Tuesday when German Chancellor Angela Merkel became the first world leader to attack her compatriot’s handling of the row.

Merkel said that the pope’s move could not be allowed to pass "without consequences" and called on the Vatican to "clarify unambiguously that there can be no denial" that the Nazis killed six million Jews.

Merkel’s comments prompted the Vatican to deny any ambiguity in the pope’s stance.

Vatican spokesman Federico Lombardi said the pope’s condemnation of the bishop "could not have been clearer." Lombardi added that "the pope’s thoughts on the subject of the Holocaust were expressed with great clarity” in the Cologne synagogue, in August 2005, and in the Auschwitz-Birkenau concentration camp on May 28, 2006.

Again on Jan. 28, the Vatican spokesman said Benedict expressed his "full and indisputable solidarity" with Jews when he said: "The Shoah (Holocaust) should be a warning for all against forgetting, denial and reductionism."

The return of Williamson into the fold came days before the 64th anniversary of the liberation of Auschwitz, the most notorious of the Nazis’ extermination camps where over a million Jews, Roma, gays and others perished.

The fallout from the row has already seen Israel’s chief rabbinate cancelled its participation in a meeting with Catholic officials in Rome in March, ahead of a planned papal visit to Israel in May that now may not take place as scheduled.

The eminent German liberal Catholic theologian Hermann Haering even went as far as calling for the Pope to step down.

The Vatican’s change of position Wednesday came after Cardinal Tarcisio Bertone, the Vatican’s secretary of state, declared the matter "closed" Tuesday in the Catholic daily Avvenire.

Wednesday’s Vatican statement also outlined as an "indispensable condition" of future recognition that the Priestly Association of Saint Pius X, to which the rebel bishops belonged, must "fully recognize" the reformist Vatican II Council of 1962-65 and the popes who followed it.

AFP/Expatica