Francis made no mention of his wartime predecessor during his talks with members of the International Jewish Committee for Interreligious Consultations (IJCIC), but the pontiff repeated the Roman Catholic Church's condemnation of anti-Semitism.
"The Jewish community continues to be concerned about efforts to canonize Pope Pius XII while innumerable documents pertaining to the history of the Church and the Jewish people during the dark years of the Holocaust still remain closed to outside scholarly investigation," IJCIC chairman Lawrence Schiffman told the pope on Monday.
The issue of whether the Vatican and the Church under Pius did all they could to help Jews has dogged Catholic-Jewish relations for decades. Pius became pontiff in 1939, the year World War II broke out, and reigned until 1958.
Pope's meeting with Jewish leaders (Photo: EPA/OSSERVATORE ROMANO)
Critics accuse Pius of failing to take action to stop the Holocaust but his supporters say he worked actively behind the scenes to encourage the Church to save Jews. They say speaking out more forcefully would have worsened the situation for all.
Jews have asked that the process, still in its early stages, that could eventually make Pius a saint be frozen until after all the Vatican's wartime archives have been opened and studied by scholars. The bulk is expected to be released next year.
At Monday's meeting, the first between the pope and an international Jewish organization since his election in March, Francis did not mention Pius but when he was archbishop of Buenos Aires he expressed support for opening Vatican archives.
"Due to our common roots, a Christian cannot be anti-Semitic," he told the delegation from IJCIC, an umbrella group that represents most major Jewish organizations and all streams of Jewish thought.
Francis, who had good relations with Jews in Argentina and wrote a book with Argentine Rabbi Abraham Skorka, told the delegation the Church was committed to the Second Vatican Council document Nostra Aetate (In Our Times).
The 1965 declaration, which Francis called "a key point of reference for relations with the Jewish people", revolutionized those relations by repudiating the concept of collective Jewish guilt for the death of Jesus and urging dialogue with Jews.
A participant at the meeting called the atmosphere "extremely friendly" and less formal than in meetings with Francis' predecessor Benedict.
Francis reached out to the Jewish community a day after his election on March 13 as the first non-European pope in 1,300 years by sending a message to Rome's chief rabbi and inviting him to his inaugural Mass at the Vatican.
Both of Francis's two immediate predecessors, John Paul II and Benedict XVI, visited the Holy Land, including the Palestinian territories, in 2000 and 2009 respectively.