Pope Leo XIV called for a just and lasting peace in Ukraine and an immediate ceasefire in Gaza with the release of hostages and delivery of humanitarian aid in his first Sunday noon blessing aspontiff.
“No more war!” Leo said from the loggia of St. Peter’s Basilica.
Recalling the end of World War II 80 years ago, Leo quoted Pope Francis in denouncing the number of conflicts ravaging the globe today, saying it was a “third world war in pieces”.
One of your browser extensions seems to be blocking the video player from loading. To watch this content, you may need to disable it on this site.
Leo also recalled that Sunday was Mother’s Day in many countries and wished all mothers, “including those in heaven” a Happy Mother’s Day.
The crowd, filled with marching bands in town for a special Jubilee weekend, erupted in cheers and music as the bells of St. Peter’s Basilica tolled.
The midday prayer drew thousands of people anxious for a closer look at the modest pontiff, born Robert Francis Prevost, who before becoming the first US pope spent much of his life as a missionary in Peru.
Read moreProgressive outreach, traditional doctrine? Where Pope Leo XIV stands on the key issues
Cardinals chose Leo as the 267th pope at a secret conclave Thursday, praying he could heal rifts within the Church, renew faith among the world's 1.4 billion Catholics and address a host of modern-day challenges weighing on the more than 2,000-year-old institution.
Addressing cardinals on Saturday, the 69-year-old Leo called himself a "humble servant of God... and nothing more than this", and an "unworthy successor" to Saint Peter, according to a transcript of his speech released by the Vatican.
Tribute to Francis
In the first clues as to the direction of his pontificate, he said he would be driven by the legacy of his predecessor, Pope Francis – who died April 21 aged 88 – "with his example of complete dedication to service and to sober simplicity of life".
Read morePope Francis, first Latin American pontiff and champion of the forgotten
On Saturday, Leo prayed before Francis's simple marble tomb inside Santa Maria Maggiore basilica. The church was a favourite of Francis and faithful have continued to line up to pay their respects there.
Cardinals describe the Chicago-born Leo as in the mold of Francis, with a commitment to the poor and disadvantaged, and a focus on Catholics in far-flung areas of the Church away from Rome.
As an Augustinian and former missionary, he also believes the Church is committed to "the missionary conversion of the entire Christian community", as he told cardinals.
Before visiting Francis's tomb, Leo made a surprise outing Saturday to an Augustinian shrine southeast of Rome, the Basilica Sanctuary of the Mother of Good Counsel.
Cardinals have described the new pope's personal style as less direct than the sometimes impulsive Francis, a progressive who shook up the Church and often ruffled feathers within the Roman Curia, or government of the Holy See, during his 12-year papacy.
Cardinal Timothy Dolan, the conservative archbishop of New York, called his fellow countryman "a man of deep faith, rooted in prayer and capable of listening".
"This is what gives us hope; not a political programme or a communicative strategy but the concrete testimony of the Gospel," Dolan told Italian newspaper La Stampa.
Soon after being elected Thursday, the soft-spoken Leo's first appearance at the balcony of Saint Peter's saw him wish peace to "all the people, wherever they are.. to the whole Earth".
Now for journalists, diplomats
Leo's Regina Coeli prayer to the Virgin Mary, that is recited particularly during Easter, kicks off a busy week of meetings and audiences.
On Monday, he will be officially presented to the international media who came to Rome to cover his election.
He plans to meet diplomats to the Vatican on Friday and then on Sunday May 18 he presides over the inaugural mass at Saint Peter's to mark the beginning of his pontificate.
The following week is marked by Leo's first general audience on May 21 – a normally weekly event by the pope that includes readings from Scripture and a homily for the public.
He also plans to meet with members of the Roman Curia and Vatican officials on May 24.
In one of his first decisions, Leo has already said the heads of dicasteries, or Vatican departments, will keep their positions for now. Those roles had been suspended between Francis's death and the new pope's election.
"The Holy Father wishes to reserve some time for reflection, prayer and dialogue, before any definitive appointment or confirmation," the Vatican said.
Meanwhile, the pontiff begins his tours to take possession of Rome's four papal basilicas – including a visit to Santa Maria Maggiore on May 25, where his predecessor Pope Francis is buried.
Francis named Leo a cardinal in 2023 after choosing him to lead the powerful Dicastery of Bishops, which advises the pontiff on bishop appointments.
But he has been largely unknown outside the Vatican.
He spent approximately two decades in Peru on missions, a central priority of the Augustinian order, taking Peruvian citizenship and learning Spanish – which he used during his first address from Saint Peter's Basilica.
(FRANCE 24 with AFP and AP)