ROME — Pope Francis decided at the last minute to skip his homily during Palm Sunday Mass in St. Peter’s Square, avoiding a strenuous speech at the start of a busy Holy Week that will test his increasingly frail health.

Pope Francis celebrates the Palm Sunday mass in St. Peter’s Square at the Vatican on Sunday. Alessandra Tarantino/Associated Press

Hobbled by bad knees and persistent respiratory problems, Francis also didn’t participate in the procession of cardinals around the obelisk in the piazza at the start of the Mass. Instead, the 87-year-old pontiff blessed the palm fronds and olive branches carried by the faithful from the altar.

Francis had been expected to deliver a homily halfway through the service, even though he had delegated long remarks to aides over the past several weeks. But after several seconds of silence, announcers said Francis had decided not to deliver the homily at all. Vatican officials didn’t immediately explain why.

Francis though did pronounce prayers throughout the service and offered a long appeal for peace at the end of the Mass. He said he was praying for the families of those killed in what he called an “inhuman” attack at a suburban Moscow concert hall and also asked for prayers for “the martyred Ukraine” and the people of Gaza.

Vatican officials estimated some 60,000 people attended the Mass, held under a sunny, breezy spring sky. Francis spent several minutes greeting them from the popemobile, making several loops around the piazza at the end of the service.

Palm Sunday kicks off a busy week for Francis leading up to Easter Sunday when the faithful commemorate the resurrection of Christ. On Thursday, Francis is due to travel to a Rome women’s prison for the traditional washing of the feet ritual. On Friday he is scheduled to preside over the nighttime Way of the Cross procession at Rome’s Colosseum re-enacting Christ’s crucifixion.

The following day marks the Easter Vigil, during which Francis presides over a solemn nighttime service in the basilica, followed by Easter Sunday Mass in St. Peter’s Square and his noontime blessing from the loggia above.

Off and on this winter, Francis has been battling what he and the Vatican have described as a case of the flu, bronchitis, or a cold. For the last several weeks he has occasionally asked an aide to read aloud his speeches and catechism lessons to spare him the effort.

On Sunday, there was no substitute called in, and the homily was merely skipped. The Vatican didn’t immediately say if his prepared remarks were to be considered as delivered, as is often the case when the pope decides not to read them aloud.

Usually, the pope doesn’t deliver a homily at Easter, but he traditionally offers reflections on Palm Sunday.

At the end of the Mass, Francis offered a long prayer for peace for all those suffering from war, and for the Lord to comfort the victims of the “vile terrorist attack” in Moscow.

“May he convert the hearts of those who protect, organize and carry out these inhuman acts that offend God, who commanded us not to kill,” Francis said.

Without citing Moscow, Francis also asked the faithful not to forget Ukraine’s suffering. He noted many Ukrainians are now without electricity as a result of “intense attacks on infrastructure, which not only bring death and suffering, but also the risk of a humanitarian catastrophe of even bigger dimensions.”

“Please don’t forget the martyred Ukraine,” he said. “And let us also think of Gaza, which is suffering so much, and so many other places of war.”