Pope Francis has visited the Portuguese town of Fatima to pray for peace at a shrine that has captivated Catholics for a century.

The shrine is known for apocalyptic prophesies of hell, peace and Soviet communism that have found new relevance with Russia’s war in Ukraine.

Francis spent the morning in Fatima, praying with sick people and prisoners, alongside pilgrims who began filling the shrine’s central esplanade long before sunrise.

As Francis prayed before a statue of the Madonna, nearby wildfires turned the sky smoky black and sent ash flittering down on the crowd.

Pope Francis arrives at Our Lady of Fatima shrine in Fatima, central Portugal
Pope Francis arrives at Our Lady of Fatima shrine in Fatima, central Portugal (Francisco Seco/AP)

Vatican Media had said Francis would pray for peace in Ukraine and the world while in Fatima.

But for the third time this trip, Francis ditched his prepared remarks and did not even recite a prayer that had been prepared for the occasion.

Instead, he offered a meditation on the welcoming embrace of the Virgin Mary, to whom the shrine is dedicated.

In explaining the changes, Vatican spokesman Matteo Bruni said Francis “always addresses firstly the people he meets, as a shepherd, and speaks accordingly”.

The 86-year-old often deviates from his prepared remarks, even more so when speaking in his native Spanish.

Mr Bruni denied the changes had any other serious reason, including with his eyesight.

Pope Francis meets young people with disabilities at the Catholic holy shrine of Fatima, in central Portugal
Pope Francis meets young people with disabilities at the Catholic holy shrine of Fatima, in central Portugal (Gregorio Borgia)

Fatima bishop Jose Ornelas made a prayer for Ukraine explicit in his remarks.

“We associate ourselves to Your Holiness’s prayer for peace, for which this sanctuary is profoundly identified, thinking in particular of the war in Ukraine and so many other conflicts in the world,” he said.

The trip was a brief excursion from Lisbon, where Francis has been presiding over World Youth Day celebrations, the big Catholic jamboree that has gathered nearly one million young Catholics together.

He returns to the Portuguese capital for a Saturday night vigil service and will then preside over a final Mass on Sunday, where the site of the next edition of the faith festival will be announced.

The Fatima story dates back to 1917, when according to tradition, Portuguese siblings Francisco and Jacinta Marto and their cousin Lucia said the Virgin Mary appeared to them six times and confided to them three secrets.

The first two described an apocalyptic image of hell, foretold the end of the First World War and the start of the Second World War, and portended the rise and fall of Soviet communism.

Pope Francis arrives surrounded by bodyguards at Our Lady of Fatima shrine in Fatima, central Portugal
Pope Francis arrives surrounded by bodyguards at Our Lady of Fatima shrine (Francisco Seco/AP)

The children were between seven and 10 years old.

At the time of the apparitions, Europe was still in the grip of the First World War and Portugal’s Catholic Church was facing a crisis after Portugal became a republic in 1910.

The republican government introduced a host of anti-clerical laws, including prohibiting religious teaching at schools.

In that context, in which priests and bishops were exiled, the visions helped reinvigorate a persecuted church.

In 2000, the Vatican disclosed the long-awaited third secret, describing it as foretelling the May 13 1981 assassination attempt against St John Paul II in St Peter’s Square, which fell on the anniversary of the original vision.

Worshippers await the arrival of Pope Francis at Our Lady of Fatima shrine in Fatima, central Portugal
Worshippers await the arrival of Pope Francis at Our Lady of Fatima shrine in Fatima, central Portugal (Francisco Seco/AP)

According to later writings by Lucia, who became a nun and died in 2005, Russia would be converted and peace would reign if the pope and all the bishops of the world consecrated Russia to the “Immaculate Heart of Mary”.

Lucia later claimed that John Paul fulfilled that prophecy during a 1984 Mass, even though he never specified Russia in the prayer.

Last year, in a prayer for peace following Russia’s invasion of Ukraine, Francis corrected the 1984 omission and consecrated both Russia and Ukraine to Mary.

Francis has made repeated appeals for an end to Russia’s war, frequently expressing solidarity with the “martyred” Ukrainian people while refraining from criticising Russia by name.

Recently, he sent an envoy to Kyiv, Moscow and Washington on a mission to try to facilitate the return of Ukrainian children taken to Russia.

Portuguese babies were out in force on Saturday and Francis took his time kissing them from his perch on the popemobile as he made his way to the central sanctuary to pray before the Madonna statue.

Lodged in her crown is the bullet casing from the 1981 attempt on John Paul’s life; on Saturday Francis placed a gilded rosary at her feet.