"Thank you for your prayer of silence," Rabbi Schudrich told Pope Francis. "Pray for me," the pope responded.

"It just felt like this silent struggle," the singer said of her experience. "And there is some pressure, whether it's put on myself or society or whatever, to not talk about it."

The think tank will convene a summit in December seeking solutions to the global refugee crisis.

"It is almost incomprehensible that today...Muslim extremists are torturing and killing innocent and unarmed Christian women and children," Cardinal Wuerl said.

Pope Francis will encounter a deeply emotional story of both betrayal and salvation during a somber visit Friday to the former Nazi German death camp of Auschwitz-Birkenau, where some 1.1 million people were murdered, most of them Jews.

Welcoming Pope Francis to the cathedral meeting, Archbishop Gadecki said the pope's task was to "care for the unity, wholeness and inviolability of Christ's teaching."