Organisers reported that more than one million people filled the streets of Madrid on Sunday to attend an open-air Mass celebrated by Pope Leo XIV in the Spanish capital.

The pontiff acknowledged the crowds while traveling through the city in his popemobile on the second day of his official visit, with King Felipe VI and Queen Letizia among those present at the morning service.

Worshippers waved Spanish and Vatican flags, shouted "long live the Pope," and scattered petals as he arrived at the Plaza de Cibeles.

In his sermon he called on the faithful to show their belief by assisting others, explaining that God "identifies with the poor, the downtrodden, those who are alone and forsaken".

He added that religion should be viewed not as "a museum of the past to be visited, but a school of faith from which to draw even today".

Authorities deployed a large security operation for the Mass and the following procession through central Madrid.

The streets featured banners displaying the Pope's image and thousands of white and yellow carnations matching the colours of the Vatican flag.

"I have come to meet Jesus Christ through the words of the Pope," 30-year-old Marta Perez told AFP on Sunday. "He's come to do good, with all his love."

Ana Milagros, 64, said the Pope was seeking to "help all of us".

"There is a lot of polarisation and differences in politics, in social matters, in the economy," she said.

Late on Saturday the pontiff joined around 500,000 worshippers, mostly young people, for a prayer vigil near Real Madrid's Santiago Bernabeu stadium that continued into the night.

"In the face of the emptiness of indifference and compliance, before the violence of war and lies, you must be the sparks of a new humanity," he told the gathering.

His comments echoed remarks made at his royal reception, where he commended Spain's dedication to peace and its "faithful adherence to international law".

The country's socialist Prime Minister Pedro Sanchez has disagreed with US President Donald Trump over the US and Israel's conflict with Iran, and with Israel over the war in Gaza. The Chicago-born pope has also faced criticism from the president regarding his anti-war stance.

His visit to Spain, the first by a pope in about 15 years, includes an address to the Spanish parliament and a meeting with victims of sexual abuse in the Catholic Church.

Pope Leo will also travel to the Canary Islands with Prime Minister Sanchez later in the week to honour thousands of migrants who have died attempting to reach Europe.