VATICAN CITY — Pope Francis celebrated Palm Sunday Mass in the shelter of St. Peter’s Basilica without the public because of the coronavirus pandemic, while parish priests elsewhere in Rome took to church rooftops and bell towers to lead services so at least some faithful could follow the familiar ritual.

Looking pensive and sounding subdued, Francis led the first of several solemn Holy Week ceremonies that will shut out rank-and-file faithful from attending, as Italy’s rigid lockdown measures forbid public gatherings.

Normally, tens of thousands of Romans, tourists and pilgrims, clutching olive tree branches or palm fronds would have flocked to an outdoor Mass led by the pontiff. Instead, Francis celebrated Mass inside St. Peter’s Basilica, which seemed even more cavernous than usual because it was so empty.

Besides his aides, a few invited prelates, nuns and laypeople were present, sitting solo in the first pews and staggered far apart to reduce the risks of contagion. A male choir, also practicising social distancing, sang hymns, accompanied by an organist.

Francis is also the bishop of Rome, and some of the parish priests in the Italian capital went to unusual lengths — or, more precisely, unusual heights — so their parishioners could follow Mass without resorting to streamed versions on TV or computers. The priests celebrated Mass on rooftops so faithful who lived nearby could watch from balconies or terraces. In one church, a priest marked Palm Sunday with Mass in the narrow confines of his church’s bell tower.

Social-distancing requirements affected Palm Sunday practices around the globe. In Jerusalem, where thousands of pilgrims usually participate in the march, this year was limited to a handful of participants. Clerics and faithful went door to door often throwing the branches to Christians looking on from their balconies.

“This year because of the new situation we are trying to come to all the Christians in our Christian Quarter to bring these branches of olives, the sign of new hope,” said the Rev. Sandro Tomasevic, a Catholic clergyman at the Latin Parish of Jerusalem. Palm Sunday commemorates Jesus’ entry into Jerusalem.

In the pope’s native Argentina, the faithful were using plants at home for a “virtual” blessing during live-streaming of Palm Sunday services.

In the United States, Rhode Island Gov. Gina Raimondo directed churches not to make palm branches available in a kind of “grab and go” pickup strategy. In a tweet, Roman Catholic Bishop Thomas Tobin urged parishes to comply with the governor’s order.

Wearing red robes to symbolize the blood shed by Jesus in the hours of his crucifix, Francis blessed braided palms.

“Today, in the tragedy of a pandemic, in the face of the many false securities that have now crumbled, in the face of so many hopes betrayed, in the sense of abandonment that weighs upon our hearts, Jesus says to each one of us: ‘Courage, open your heart to my love,’” Francis said.

Francis urged people to hold fast to “what really matters in our lives.”

“The tragedy we are experiencing summons us to take seriously the things that are serious, and not to be caught up in those that matter less, to rediscover that life is of no use if not used to serve others,” the pontiff said in his homily.

In a remark directed to young people, Francis said: “Dear friends, look at the real heroes who come to light these days: they are not famous, rich and successful people.”

Instead, he said, “they are those who are giving themselves in order to serve others. Feel called yourselves to put your lives on the line.”

Earlier during the pandemic, Francis has praised medical staff, transport workers, supermarket clerks and others for their sacrifices to help lives.

“May we reach out to those who are suffering and those most in need,” the pope said. “May we not be concerned with what we lack, but what good we can do for others.”

Francis said that youth in Panama would have symbolically passed a cross on Sunday to others in Lisbon, Portugal, which will host the next Catholic world youth jamboree in 2022. Francis announced that the handover ceremony would take place instead on Nov. 22.

Noting that sports events are canceled, the pontiff said the “best fruits of sport” are evident these times: “resistance, team spirit, brotherhood, giving the best of oneself.”

At the end of Mass, Francis called on faithful to spiritually draw close to the sick, their families and those treating them and to offer prayers for the deceased.

“May we reach out to those who are suffering and those most in need,” the pope said. “May we not be concerned with what we lack, but what good we can do for others.”

Palm Sunday opens Holy Week leading up to Easter, which this year falls on April 12. Among the usual events is the Good Friday Way of the Cross procession. This year, instead of the customary candlelit procession at Rome’s Colosseum, the Way of the Cross will be presided over by Francis in St. Peter’s Square without the public, in keeping with Italian and Vatican anti-contagion bans on gatherings.

The Vatican has said there are seven cases of COVID-19 among the residents or employees of the tiny independent city state. The virus causes mild to moderate symptoms in most people, but for some, especially older adults and the infirm, it can cause pneumonia and lead to death.