NEW YORK (AP) _ Rabbi Marc Tanenbaum, a pioneer in promoting Vatican-Jewish relations and the former international affairs director for the American Jewish Committee, died on Friday. He was 66.

Tanenbaum, who underwent heart surgery last month, died of heart failure at Lenox Hill Hospital, said his wife, Georgette Bennett.

For decades, the New York-based rabbi was a powerful voice of American Judaism in the world, active in promoting good relations between Jews and members of other faiths.

He became a prominent figure on the international scene in 1965 when he was the only Jew to participate in the Second Vatican Council that decried anti- Semitism and banned the Roman Catholic Church's depiction of Jews as Christ-killers.

In 1987, when Pope John Paul II offended many Jews by meeting with Austrian President Kurt Waldheim, who was accused of being a former Nazi, Tanenbaum flew to Rome to mend fences.

As a result, many jokingly dubbed him ''the foreign minister of the Jews,'' Bennett said.

The rabbi's friends in his interfaith work included South African Archbishop Desmond Tutu, the Rev. Billy Graham and New York Cardinal John O'Connor.

But his forays into the Christian world cost him the wrath of some Orthodox Jews, who refused to call him ''rabbi.''

A native of Baltimore, Tanenbaum moved to New York as a child, attended an Orthodox Jewish Yeshiva and was ordained in 1950 at Manhattan's Jewish Theological Seminary.

In recent years, he was involved in work for the human rights of refugees and in trying to ease world hunger. Just after the fall of the Iron Curtain, Tanenbaum was among the first to assist the exit of Albania's Jews to the West after decades of repression.

He was on the board of directors of the International Rescue Committee for refugees, and also worked for the American Jewish World Service, a non- denominational organization dealing with Third World development and hunger problems.

Tanenbaum retired as international affairs director of the American Jewish Committee in 1989.

In addition to his wife, he is survived by three grown children from a previous marriage, and a sister.