By Joshua McElwee, Crispian Balmer and Philip Pullella, Reuters
Pope Leo XIV greets the crowd from the popemobile before a Holy Mass in St Peter's Square. Photo: ALBERTO PIZZOLI
Pope Leo XIV rode into St Peter's Square on a 'popemobile' for the first time on Sunday, as tens of thousands of people - including dozens of world leaders - celebrated him as the new leader of the world's 1.4. billion Catholics.
Crowds crammed the square and surrounding streets in Rome in the biggest gathering at the Vatican since the funeral of Leo's predecessor, Pope Francis, on 26 April.
Wellwishers carried US and Peruvian flags to cheer the first pope from the United States, who celebrated his inaugural Mass later on Sunday morning (local time).
Pope Leo XIV greets the crowd from the popemobile. Photo: AFP / Pool / Jacquelyn Martin
Born in Chicago, the 69-year-old pontiff spent many years as a missionary in Peru and also has Peruvian citizenship, meaning he is also the first pontiff tied to that South American nation.
One person in the crowd shouted out "White Sox, White Sox", referring to the Chicago baseball team at the bottom of the American League standings. Leo has never abandoned the team, despite their recent lacklustre performance, and his fellow diehard fans hope his support can lift them out of the doldrums.
People chanted "Viva il Papa" (Long Live the Pope) and "Papa Leone", his name in Italian.
The open-topped popemoble was surrounded by more than a dozen security guards, as it drove through the square and down the long boulevard that leads to the Tiber River, for Leo's first ride.
The vehicle moved quickly, but briefly stopped twice, so Leo could bless three babies.
The popemobile stopped twice, so Leo could bless babies. Photo: ALBERTO PIZZOLI
Robert Prevost - a relative unknown on the world stage, who only became a cardinal two years ago - was elected pope on 8 May, after a short conclave of cardinals that lasted barely 24 hours.
He replaces Pope Francis from Argentina, who died on 21 April, after leading the church for 12 often-turbulent years, during which he battled with traditionalists and championed the poor and marginalised.
US Vice President JD Vance, a Catholic convert who clashed with Francis over the Trump administration's hard-line immigration policies, led a US delegation, alongside Secretary of State Marco Rubio, who is also Catholic.
Usha Vance, right, and Vice President JD Vance are greeted by Bruno Pasquino from the Italian Ministry of Foreign Affairs and Monsignor Christopher Washington of the Holy See Secretariat. Photo: AFP / pool / Jacquelyn Martin
Ukrainian President Volodymyr Zelensky also attended and was happy to meet other leaders, a top aide said, as he did at Francis' funeral, when he had face-to-face talks with US President Donald Trump in St Peter's Basilica.
Zelensky last met Vance in February at the White House, when the two men clashed fiercely in front of world media.
Also expected at the Vatican ceremony were the presidents of Peru, Israel and Nigeria, the prime ministers of Italy, Canada and Australia, German Chancellor Friedrich Merz and European Commission President Ursula von der Leyen.
Many European royals were also be in the VIP seats near the main altar, including Spanish King Felipe and Queen Letizia.
Focus on peace
In various sermons and comments since his election as pope, Leo has praised Francis repeatedly, but has not offered many hints about whether he will continue with the late pontiff's vision of opening the Church up to the modern world.
Pope Leo addresses the crowd from the main central loggia balcony of the St Peter's Basilica for the first time. Photo: AFP
His first words in an appearance to crowds in St Peter's Square on the night of his election were "Peace be with you all", echoing words Catholics use in their celebrations.
In a 14 May address to officials of the eastern Catholic Churches - many of whom are based in global hotspots such as Ukraine and the Middle East - the new pope pledged he would make "every effort" for peace.
He also offered the Vatican as a mediator in global conflicts, saying war was "never inevitable".
Sunday's Mass would feature prayers in several languages, in a nod to the global reach of the 1.4-billion member Church, including Latin, Italian, Greek, Portuguese, French, Arabic, Polish, and Chinese.
As part of the ceremony, Leo would also formally receive two items, as he takes up the papacy - a liturgical vestment known as a pallium, a strip of lambswool that represents his role as a shepherd, and a special band known as the fisherman's ring.
The ceremonial gold signet ring is specially cast for each new pope and can be used by Leo to seal documents. It features a design of St Peter holding the keys to heaven and will be broken after his death, marking an end to his papacy.
- Reuters