Pope Francis is expected to leave hospital on Saturday pending the results of his latest medical tests and is scheduled to take part in a Palm Sunday service the following day, the Vatican said on Friday.

The pope, 86, was taken to Rome's Gemelli hospital two days ago after complaining of breathing difficulties. He was diagnosed with bronchitis and has responded well to an infusion of antibiotics, the medical team has said.

"His Holiness is expected to return to Santa Marta tomorrow, once the results of the latest tests from this morning are known," the Vatican said, referring to a residence next to St. Peter's Basilica where the pope lives.

Highlighting the pope's improved health, the Vatican said he had pizza on Thursday night in hospital with his doctors, nurses, assistants and security personnel.

Vatican spokesman Matteo Bruni confirmed that if Francis does indeed return home on April 1, he would take part the following day in a service for Palm Sunday - a major event in the Church calendar that kicks off Easter week celebrations.

Holy Week, as it is known, includes a busy schedule of rituals and ceremonies that can be physically exhausting, including a Good Friday nighttime procession by Rome's Colosseum.

The dean of the college of cardinals, Giovanni Battista Re, has said a cardinal would help the pope during the week's celebrations and take care of altar duties.

A similar arrangement was put in place last year, when the pope sat to one side during some Easter events due to persistent knee pain, leaving it to senior cardinals to lead the Masses.

The pope, who marked the 10th anniversary of his pontificate earlier this month, has suffered a number of ailments in recent years. Francis was last hospitalized in July 2021 when he had part of his colon removed in an operation aimed at addressing a painful bowel condition called diverticulitis.

"When experienced with faith, the trials and difficulties of life serve to purify our hearts, making them humbler and thus more and more open to God," the pope tweeted on Friday.