Vast crowds thronged one of the main boulevards in Buenos Aires on Monday as Pope Leo hailed the strength of the Catholic Church in South America at an outdoor Mass that drew a record 2.5 million people on the first papal trip to Argentina in 39 years.

Argentines stretched for miles down Avenida del Libertador, waving the white-and-yellow Vatican flag and pressing against security barriers for a glimpse of the pontiff. It was the largest event to date of the pope's 18-month tenure leading the global Catholic Church.

Chants of "Long live Pope Leo!" echoed down the tree-lined street as the pope, on the second leg of a 12-day trip to South America, was driven by in an open-top popemobile under sunny skies.

Leo said in his sermon how happy he was to see Catholics in a region that has long been a stronghold for the Church but where it has been losing ground recently to fast-growing evangelical denominations.

"It fills my heart with joy to celebrate... with you," said the pope. "My visit to this land of Argentina has allowed me to see on your faces the enthusiasm of your faith."

Leo, 71, is on an ambitious 50-event, three-country tour less than a month after undergoing lung cancer surgery. He visited Uruguay before arriving in Argentina on Sunday and will travel on to Peru on Wednesday before returning to Rome on November 17.

The first US-born pope spent decades as a missionary in Peru and the Vatican has described the tour, one of the most demanding foreign tours by a pope in decades, as a "homecoming".

People had gathered in the early hours of Monday ahead of the Mass. Some normally bustling parts of the city stood near-empty as police cordoned off a security zone.

"I love that (Leo) is visiting us," said Claudia Pardo, 37, who waited for Leo with her husband and two young children. "It's a unique, historic moment, and we should listen to his message."

Alejandra Frias, 56, was sleepless after camping out all night to get a front-row view of the pope. "This is an emotional and spiritual moment," she said.

A pope has not visited majority-Catholic Argentina since 1987. Francis, Leo's predecessor, never made it back to his home country after ascending to the papacy.

Leo has emerged as a forceful voice on the world stage, lamenting what he sees as a failure of global leadership. On his tour he has urged South American nations to set an example of regional cooperation and patient diplomacy instead of conflict.

On Sunday, the pope addressed Argentine President Javier Milei, a libertarian and ally of US President Donald Trump. He urged Milei, who has pushed an austerity agenda that the Church has strongly criticised for cutting social services, to not target Argentina's poorest.

He also told Milei, a theatrical figure known for bombastic statements, that leaders should be careful with their words and know the limits of their power.

The pope lamented the difficulties faced by Argentine families at the Mass on Monday. He said they are enduring "instability, social hardship, precarious employment, domestic violence, painful separations and addictions that destroy young people's futures and damage family relationships."

Later, in a meeting with labourers and union leaders, the pope decried corporate greed and urged that workers be treated with respect. "The economy ... must be at the service of the person, and not the person at the service of the economy," he said to applause from the group.

The pope, who has warned that artificial intelligence could lead the world down a path of unending war, also expressed concern that "unregulated automation can put countless jobs at risk."

Leo also met on Monday with five victims of sexual abuse by Catholic clergy, one of several such meetings he is expected to have on his trip as the Church seeks to repair its standing after abuse scandals tarnished its reputation. (Reuters)



Edited by Cecil Wong