Volkswacht Bodensee - Catholics gather to catch glimpse of Pope Leo XIV at St Peter's prayer

The noon (1000 GMT) prayer is expected to draw thousands of people anxious for a closer look at the modest pontiff, born Robert Francis Prevost, who before becoming the first pope from the United States spent much of his life as a missionary in Peru.

Cardinals chose Leo as the 267th pope at a secret conclave on 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 St Peter, according to a transcript released by the Vatican.

A steady stream of pilgrims and worshippers began to gather in St Peter's Square on Sunday morning, bearing flags and Catholic symbols from across the globe. Priests and nuns mingled with the crowds, with many groups of young people, some playing guitars and singing songs.

Resfina Macoy Torrevillas, a 68-year-old from San Diego, California, said Leo's Sunday appearance would be the "highlight" of her group's pilgrimage.

"We're hoping for a good year, because the Catholic Church is challenged right now, especially in the USA."

She hoped the new pope could help mend that: "God moves in mysterious ways."

- Tribute to Francis -

In the first clues as to the direction of his pontificate, Leo said Saturday he would be driven by the legacy of his predecessor, Pope Francis -- who died on April 21 aged 88 -- "with his example of complete dedication to service and to sober simplicity of life".

Leo made an unannounced visit to pray before Francis's simple marble tomb inside Santa Maria Maggiore basilica in the early evening on Saturday. The church was a favourite of Francis and worshippers have continued to line up to pay their respects there.

Cardinals describe Leo as in the mould of Francis, with a commitment to the poor and disadvantaged, and a focus on Catholics in far-flung areas away from Rome.

As an Augustinian and former missionary, he also believes the Church should be committed to "the missionary conversion of the entire Christian community", as he told cardinals.

Before visiting Francis's tomb, Leo visited an Augustinian shrine southeast of Rome, the Basilica Sanctuary of the Mother of Good Counsel -- underscoring the importance to the new pontiff of the religious order, which is focused on community and collaboration.

The new pope's personal style is seen to be 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 Pierbattista Pizzaballa, the Latin Patriarch of Jerusalem, described Leo as "a person who immediately inspires a lot of confidence, a mild man who knows how to listen..."

"We are at the beginning of his pontificate, but already the first steps give us great courage and comfort. Even the reaction of the people, so beautiful and enthusiastic, says a lot," Pizzaballa told the Corriere della Sera daily on Sunday.

- Now for journalists, diplomats -

Leo's Regina Caeli prayer to the Virgin Mary, recited at Easter and its aftermath, 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 will preside over the inaugural mass at St 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 which 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 scheduled visit to Santa Maria Maggiore on May 25.

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, taking Peruvian citizenship and learning Spanish -- which he used during his first address on Thursday from St Peter's Basilica.

A.Ruegg--VB