ROME — Pope Francis met a U.S. special envoy for anti-Semitism Thursday amid the developing war between Israel and Hamas, with the diplomat later saying the pontiff had referred to the surprise attacks that triggered the conflict as “criminal.”

Deborah Lipstadt, who’s served as the United States Special Envoy for Monitoring and Combating Antisemitism since May 22, was in Rome participating in a conference at the Jesuit-sponsored Gregorian University on new documents recently made available by the Vatican from the reign of Pope Pius XII, who led the Catholic Church during the era of the Holocaust and the Second World War.

Lipstadt, 76, met Francis in the Vatican and later posted a picture of the encounter to her Instagram account.

“Today, I had the distinct honor of meeting with His Holiness Pope Francis,” Lipstadt wrote. “We discussed the importance of opening the Pope Pius XII archives to accurately examine history and how we must strengthen Catholic-Jewish relations by addressing antisemitism through education.”

“We also discussed the bone-chilling violence in Israel and expressed our great concern for the brutal terrorist attacks taking place, which Pope Francis described as criminal,” she said.

The meeting came in the wake of comments by Francis on the conflict on Wednesday which were welcomed by the Israeli ambassador to the Holy See as “filling a vacuum.”

During a general audience address Wednesday, Pope Francis appealed for all hostages be released. He also insisted “it is the right of those who were attacked to defend themselves,” while also voicing concern over “the total siege Palestinians in Gaza face, where many have also been innocent victims.”

Israeli Ambassador Raphael Schutz welcomed the statement, saying “in a way [it] fills a vacuum I felt needed to be filled in recent days, especially recognizing the right of Israel to self-defense.”

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Lipstadt, a professor of Jewish and Holocaust studies at Emory University in Atlanta, is best known for her work on Holocaust denial.

In 1996, she was sued by British author David Irving for libel after including him in her 1993 book Denying the Holocaust, even though Irving has argued that Hitler had no policy to exterminate Jews and that there were no gas chambers at Auschwitz. A British court rejected the charge, siding with Lipstadt.

Earlier this week, Lipstadt referred to the Hamas attack on Israel as “the deadliest assault against Jews since the Holocaust.”

Since the conflict began on Saturday, the death toll in Israel has reached 1,300, with more than 3,000 people injured, according to Israeli government figures. In Gaza, retaliatory airstrikes from Israel have killed 1,417 Palestinians and wounded more than 6,250, according to the Hamas-run Gaza Health Ministry.

Lipstadt’s encounter with Pope Francis came just ahead of events planned in Rome for Oct. 16, the 80th anniversary of the deportation of Roman Jews by the Nazis in October 1943. More than 1,000 Jews, including 200 children, were sent to Auschwitz, and only 16 made it back to Rome alive.

The city of Rome is hosting a series of film screenings, meetings, theatrical performances, tours and exhibitions to mark the occasion, as well as a solemn March of Remembrance on Oct. 16 led by Mayor Roberto Gualtieri.

That evening Italian President Sergio Mattarella will lay a wreath at Rome’s Synagogue, where he will be accompanied by Rome’s Chief Rabbi Riccardo Di Segni and by lay Italian historian Andrea Riccardi, founder of the Catholic Community of Sant’Egidio.