Updated

Pope Francis is asking for prayers for this week's sex abuse summit at the Vatican, calling abuse an "urgent challenge of our time."

He has summoned bishops to Rome to help him chart a way forward after decades of abuse by priests and prelates and the systematic cover-ups of that by their superiors. The scandals have eroded Catholics' trust in the Vatican and in church leaders like bishops.

Francis told pilgrims and other visitors Sunday in St. Peter's Square that beginning Thursday, the heads of episcopal conferences worldwide will discuss "protection of minors in the church."

He said: "I ask prayers for this appointment, which I wanted as an act of strong pastoral responsibility in the face of an urgent challenge of our time."