"It is scandalous that someone of this stature in the Church denies the Holocaust," the institution said in a statement, referring to Bishop Richard Williamson who has publicly denied the murder of six million Jews during World War II. "Denial of the Holocaust not only insults the survivors, memory of the victims and the righteous among the nations who risked their lives to rescue the Jews, it is a brutal attack on truth," Yad Vashem said. The Wiesenthal Centre, an international Jewish human rights body, said: "The Pope's decision to welcome back such a hater into the Church lends moral credence to deniers of history's worst crime. "In addition to Bishop Williamson's Holocaust denial looms the unchanging virulent anti-Semitism of the Society of Saint Pius as a whole," it said. The pope cancelled the ex-communication of Williamson and three other bishops in a bid to heal a 20-year schism with traditionalists led by rebel French archbishop Marcel Lefebvre. The Roman Catholic Church published an edict lifting the 1998 sanction on Lefebvre's successor Bernard Fellay and three other bishops in his breakaway conservative movement, including Williamson. He is on record as denying the existence of the gas chambers. "I believe there were no gas chambers.... I think that 200,000 to 300,000 Jews perished in Nazi concentration camps but none of them by gas chambers," Williamson was quoted as saying in an interview with Swedish SVT television. "There was not one Jew killed by the gas chambers. It was all lies, lies, lies!" Italian Jewish groups criticised the decision as a "negative, worrying and incomprehensible signal" on Saturday. Uneasy relations between the Vatican and Israel have been further strained by plans to declare Nazi-era Pope Pius XII a saint, despite widespread criticism of his inaction during the Holocaust.