ROME — As Christians around the world celebrated Christmas, Pope Francis called on Wednesday for a softening of “stony and self-centered hearts,” once again directing the world’s attention to the plight of migrants and people living in areas plagued by conflict, social and political upheaval, injustice, or natural disasters.

Addressing thousands of people gathered in St. Peter’s Square, the pope spoke of the millions of people who have fled their homes for “places where they might have hope for a dignified life,” only to find themselves “before walls of indifference.”

Making his annual Christmas speech, Francis lamented the miseries of several trouble spots, urging the rest of the world to take responsibility for healing those places and to embrace the refugees who leave them. It has been one of the most powerful and consistent messages of his papacy, at a time when many nations have shown little interest in resolving foreign conflicts or taking in migrants and have often blamed newcomers for economic and social ills.

Delivering his “Urbi et Orbi” (“To the City and to the World”) benediction from a balcony in the facade of St. Peter’s Basilica, the pope asked Jesus to “bless the efforts of those who spare no effort to promote justice and reconciliation and to overcome the various crises and the many forms of poverty that offend the dignity of each person.”