Pope Benedict outraged Jewish leaders and progressive Catholics last month when he lifted excommunications on Richard Williamson and three other traditionalists to try to heal a 20-year-old schism within the Church.

Asked why he had not apologised for his comments, Williamson told Germany's Spiegel magazine: "If I should discover that I have been at fault, then I will do so."

Williamson told Swedish television in an interview broadcast on Jan. 21: "I believe there were no gas chambers". He said no more than 300,000 Jews perished in Nazi concentration camps, rather than the 6 million accepted by mainstream historians.

"I ask everyone to believe me that I did not deliberately say something false. I was, on the basis of my research in the 1980s, convinced of the accuracy of my comments," he told the weekly in an interview released on Saturday.

"Now I must examine everything again and look at the evidence," he added.

British-born Williamson apologised to the pope late last month for the "unnecessary distress and problems" he caused him. But he did not recant or take back the Holocaust comments, which he called "imprudent".

The Vatican has said the pope was not aware of Williamson's denial of the Holocaust when he lifted the excommunications. The Vatican ordered Williamson to publicly recant if he wants to serve as a prelate in the Church.