Pope Francis is pressing his case for the Catholic Church to be more a place of mercy than moralizing with a three-day retreat for priests from around the world aimed at encouraging them to show "infinite mercy" with their flocks.

Francis kicked off the retreat's main day Thursday with a meditation on mercy at St. John Lateran Basilica. He had two other meditations scheduled later at other Rome basilicas, one of the key events of his Holy Year of Mercy which, at its half-way mark, has drawn 8.5 million pilgrims to Rome.

Francis' emphasis on mercy has come under increasing criticism from conservatives for opening the door to letting divorced and civilly remarried Catholics receive Communion. Conservatives say Francis introduced confusion in the church's teaching about the indissolubility of marriage.