The cardinals of the Catholic Church have elected Robert Francis Prevost as Pope Leo XIV, the first North American  pope.

Earlier white smoke wafted from a Sistine Chapel chimney, signaling that the 133 cardinals inside had elected a new pope to lead the world's 1.4 billion Roman Catholics.

Pope Leo is said to be a "moderate" who was close to Pope Francis.

He spent years as a missionary in Peru and he becomes the Catholic Church's 267th pontiff.

The Vatican announced his name in Latin from the balcony of St. Peter's Basilica on the evening of May 8.

Cardinal Dominique Mamberti, a 73-year-old Frenchman born in Morocco, made the announcement of a successful election to cheers from St. Peter's Basilica after voting went into a second day.

That meant the cardinal elected had secured at least 89 votes of the 133 cardinals from 70 different countries participating in the conclave to elect a successor to Pope Francis.

Francis died on Easter Monday, aged 88, April 21, and after his funeral, attention turned to the conclave - a secret meeting through which the new pope is chosen.

During the papal conclave, the cardinals were barred from leaving or having any contact with the outside world as they conferred to elect the new church leader.

When Argentine Jorge Bergoglio, who became Pope Francis, was elected in March 2013, his identity was revealed about 45 minutes after the white smoke when he appeared on the balcony above St Peter's Square.

Thousands celebrating the papal election cheered in St. Peter's Square as the Swiss Guard and band marched.

"We're seeing the Swiss Guard wearing their "distinctive, stripy colored uniform and the band that come out for major moments in the Vatican, and we expect them to play the Vatican national anthem in and around when the pope is announced, the new pope is announced," CNN's Vatican correspondent Christopher Lamb said.

Francis was elected pope after the surprise resignation of German Pope Benedict XVI.

Police said that the number of people crammed in St Peter's Square had risen to more than 40,000 while awaiting the announcement of the name of the new pope.

The fact that it took cardinals only four rounds of voting to pick a new pope and the white smoke came out of the Sistine Chapel chimney after a day's voting is "a clear sign of the unity of the Church," Italian Cardinal Giuseppe Versaldi said in the Vatican press office, the BBC reported.