VATICAN CITY (AP) — Pope Francis has blessed palm fronds and olive branches in St. Peter's Square at the start of Holy Week celebrations.

The pontiff in his Palm Sunday homily decried suffering in the world today, citing those who "suffer from slave labor, from family tragedies, from diseases ... They suffer from wars and terrorism, from interests that are armed and ready to strike."

The celebrations began with a solemn procession, with the pope and cardinals walking through the throngs gathered in St. Peter's Square clutching elaborately braided palm fronds.

The processions recalls the bittersweet nature of Holy Week, with the faithful clutching simple palm fronds and olive branches to commemorate Jesus' triumphant entrance into Jerusalem on a procession, followed later in the week with his death on a wooden cross.