Vatican City - White smoke billowed from the chimney of the Sistine Chapel on Thursday, signalling that cardinals locked inside have elected a new leader for the world's 1.4 billion Catholics.

Thousands of pilgrims and curious onlookers in St Peter's Square cheered and applauded as the smoke appeared and bells began to ring, indicating the 2,000-year-old institution has its 267th pope.

All eyes now turn to the balcony of St Peter's Basilica, to see who has been elected to succeed Pope Francis, an Argentine reformer who died last month after 12 years as leader of the worldwide Church.

The new pontiff will be introduced in Latin with his chosen papal name and address the world for the first time.

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He faces a momentous task: as well as asserting his moral voice on a conflict-torn global stage, he faces burning Church issues from the continued fall-out from the sexual abuse scandal to the Vatican's troubled balance sheets.

Some 133 "Princes of the Church" from five continents – the largest conclave ever – began voting on Wednesday afternoon.

Sworn to secrecy, on pain of excommunication, their only means of communicating their progress to the outside world was by sending up smoke through the chimney of the Sistine Chapel.

On Wednesday evening and then again on Thursday lunchtime, the smoke was black, emitting disappointed sighs from the tens of thousands watching.

But on Thursday afternoon, just after 6 PM (12:00 PM ET), the smoke emitted was white, confirming that the Catholic Church has a new spiritual leader.

Pope Leo XIV called for the world to "build bridges" and for peace for "all peoples", as he addressed the crowds in St Peter's Square following his election.

The new pontiff urged people to "build bridges through dialogue, through encounter, to come together as one people, always in peace", before paying homage to his predecessor, Pope Francis.

President Donald Trump on Thursday hailed the election of new Pope Leo XIV, the first pontiff from the US, as a "great honor" for the country.

"Congratulations to Cardinal Robert Francis Prevost, who was just named Pope. It is such an honor to realize that he is the first American Pope. What excitement, and what a Great Honor for our Country," Trump said on his Truth Social network.

"I look forward to meeting Pope Leo XIV. It will be a very meaningful moment!"

Cardinal Robert Francis Prevost has been revealed as the next pope, taking on the title of Leo XIV.

The 69-year-old Chicago native is the first American pope in the 2,000-year history of the church.

By tradition, he now enters the Room of Tears – where freshly-elected popes give free rein to their emotions – to don a papal cassock for the first time, before returning to the Sistine Chapel so the cardinals can pledge their obedience.

He will then appear on the balcony along with a senior cardinal, who will announce to the waiting crowds "Habemus Papem" ("We have a pope").

The pope will then give a short speech and impart his first "Urbi et Orbi" ("To the City and the World") blessing.