Pope Francis presided over the Palm Sunday ceremonies in St. Peter's Square at the Vatican this Sunday, marking the beginning of Holy Week, after being discharged from hospital.

Francis warned of humanity's "indifference" to millions of "abandoned" people around the world, saying that for Catholics, people who are "rejected and excluded" are "living icons of Christ".

"Let us ask for this grace today: to know how to love the abandoned Jesus and to know how to love Jesus in every abandoned person. Let us ask for the grace of knowing how to see and recognize the Lord who continues to cry out in them. Let us not allow his voice to be lost in the deafening silence of indifference," he said in his homily at Palm Sunday Mass, quoted by the Ecclesia news agency and Notícias ao Minuto.

"For us, disciples of the Forsaken, no one can be marginalized, no one can be left on their own," he added.

"There are entire peoples exploited and left to their own devices; there are poor people who live at the crossroads of our roads and whose gaze we don't have the courage to fix; migrants, who are no longer faces, but numbers; rejected prisoners, people cataloged as problems," Pope Francis said.

The celebration, which brought together thousands of people in St. Peter's Square, began with the blessing of the branches.

Due to the problems he has been suffering with his knee for several months, the Pope did not accompany the entrance procession, with around 400 participants.

Francis presided over the celebration that marks the beginning of Holy Week, after being discharged this Saturday from Gemelli Hospital, where he had been hospitalized since Wednesday due to a respiratory infection.