After recovering from illness, Pope Francis conducts the Palm Sunday service.

The day after being released from the hospital after suffering from bronchitis, Pope Francis presided over a Palm Sunday service and urged people to better care for the underprivileged, the lonely, and the sick.

Before Francis descended and began the service from beneath an ancient Egyptian obelisk in St. Peter's Square, thousands of people waved palm and olive branches as he was driven there in the back of a white, open-topped vehicle.

The pope, 86, was admitted to the Gemelli hospital in Rome on Wednesday after complaining of breathing problems, but he quickly recovered after receiving an antibiotic infusion and went back to his residence in the Vatican on Saturday.

Pope Francis addressed a crowd of 30,000 at Palm Sunday, calling on people not to ignore suffering and solitude.

"Today their numbers are legion. Entire peoples are exploited and abandoned; the poor live on our streets and we look the other way; migrants are no longer faces but numbers, prisoners are disowned; people written off as problems," he said.

Pope Francis, who marked his 10th anniversary of his pontificate in March, has suffered from severe knee pain and uses a cane and wheelchair in public appearances. He will celebrate Palm Sunday and Holy Thursday in a prison for juveniles, and participate in the traditional Good Friday Via Crucis procession. He will then preside over the Mass on Easter Sunday, where he is expected to read his "Urbi et Orbi" message.