'I believe there were no gas chambers' - Richard Williamson in November 2008
A UK-born cleric who denied the existence of Nazi gas chambers has apologised to the Pope for causing any distress - but without retracting.
Richard Williamson also thanked Pope Benedict for allowing him to rejoin the Roman Catholic Church after being excommunicated on an unrelated issue.
He apologised for his "imprudent remarks" in a Swedish TV interview.
Pope Benedict has reiterated his "full and indisputable solidarity" with Jews on the subject of the Nazi death camps.
He has been under pressure from Nobel Peace Prize winner and death camp survivor Elie Wiesel among others to distance himself from Bishop Williamson, who was promoted to bishop along with others by the breakaway Archbishop Marcel Lefebvre of France.
Bishop Williamson, who lives in Argentina, blogged his apology in an open letter to Cardinal Dario Castrillon Hoyos, the mediator between the Vatican and the breakaway Catholic faction.
The letter on Mr Wlliamson's blog did not mention the Holocaust
"Amidst this tremendous media storm stirred up by imprudent remarks of mine on Swedish television, I beg of you to accept... my sincere regrets for having caused to yourself and to the Holy Father so much unnecessary distress and problems," he said.
He made no mention of the Holocaust in the brief letter.
In an interview with Swedish TV, he had said: "I believe there were no gas chambers... I think that two to three hundred thousand Jews perished in Nazi concentration camps but none of them by gas chambers."
Vatican spokesman Federico Lombardi, contacted by AFP news agency, refused to comment on the content of the letter, saying only: "The Vatican has asked nothing of Monsignor Williamson, who is not an 'ordinary bishop' of the Catholic Church."
Bishop Williamson and three other "bishops" whose excommunications were lifted are members of the Society of St Pius X, which was founded by Archbishop Lefebvre in 1970 as a protest against the Second Vatican Council's reforms on religious freedom and pluralism.
The late Archbishop Lefebvre made them bishops in unsanctioned consecrations in Switzerland in 1988, prompting the immediate excommunication of all five by the late Pope John Paul II.
When it recently lifted their excommunication, the Vatican said the four men had been asked to recognise the authority of the Pope and the Second Vatican Council.
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