Tens of thousands of Romans, tourists and pilgrims have joined Pope Francis in a solemn Palm Sunday service in St. Peter’s Square.

Under cloudy skies, Francis celebrated Mass on the steps of the square as the crowd spread out before him. Faithful clutched olive tree branches, tall palm fronds or tiny braided palm leaves shaped like crosses.

Palm Sunday begins Holy Week, which culminates next Sunday on Easter. Francis used a pastoral staff made of wood carved by Italian prison inmates, who donated it to him. The pope is determined to put people on the margins of life at the center of the Roman Catholic church’s attention.

Francis wore red vestments, symbolizing blood shed by the crucified Jesus. On Friday, he’ll preside at the Colosseum Way of the Cross procession. (AP)