Pope Benedict XVI's pilgrimage to the Holy Land veered into controversy over his past on Tuesday when the Vatican denied and then acknowledged his membership in the Hitler Youth during World War II.

The conflicting accounts came in response to criticism by Israeli leaders that the German pontiff's address at the Holocaust Memorial on Monday had failed to acknowledge his witness of Nazi terror as a conscript in the youth movement and the German army.

Father Federico Lombardi, the Vatican's chief spokesman, felt compelled to declare that the pope, growing up as Joseph Ratzinger in Bavaria, "never, never, never" belonged to the Hitler Youth. Later he backtracked, conceding what Ratzinger, then a Roman Catholic cardinal, told an interviewer for his 1997 biography: that his membership in the movement had been compulsory.

The confusion highlighted the Vatican's defensiveness over Benedict's words at the Yad Vashem memorial, where the 82-year-old pontiff declared that Hitler's extermination of Jews must "never be denied, belittled or forgotten" but did not use the word Nazi or German. The Vatican's bumbling response risked reopening a chapter of the pope's life, discomforting to Israelis, that many had considered closed.