On Saturday evening, the pope led the traditional Christmas Eve mass at St Peter's Basilica
On Saturday evening, the pope led the traditional Christmas Eve mass at St Peter's Basilica AFP

Thousands of people are set to gather Sunday in St Peter's Square to hear Pope Francis deliver his Christmas Day message, where he is expected to offer prayers for war-torn Ukraine.

The head of the Catholic Church will address the faithful from the central balcony of St Peter's Basilica in the Vatican, before delivering the "Urbi et Orbi" blessing ("to the city and the world").

The 86-year-old is expected to focus on the brutal conflict in Ukraine in his speech, which is broadcast on television and radio around the world.

Pope Francis has called for peace ever since Russia invaded Ukraine in February, condemning the war but seeking to maintain a delicate dialogue with Moscow.

However, he has been criticised in some quarters for not being more explicit in blaming Russian President Vladimir Putin.

He has focused on the human toll of the war, weeping earlier this month as he offered prayers for a "tormented" Ukraine.

In an interview published at the end of November in the US Jesuit magazine America, the Argentine pontiff denounced the cruelty of Russia's troops in Ukraine, drawing a formal protest from Moscow.

On Saturday evening, the pope led the traditional Christmas Eve mass at St Peter's Basilica with some 7,000 people attending, according to the Vatican.

Using a wheelchair as he continues to struggle with knee pain, the pope prayed for "the children devoured by wars, poverty and injustice" and lamented that "men hungry for power and money swallow up their loved ones, their brothers".

He called on people to "abandon the warmth of worldliness" and "rediscover the meaning of Christmas" in the face of "consumerism", advocating for a Church that serves the poor.

Around 4,000 people followed the ceremony on giant screens installed outside as the world's 1.3 billion Catholics prepared to mark the holiday celebrating birth of Christ.

"It's very inspiring to be here with all these people," Victoria Machado, who travelled with her family to the Vatican from Mexico, told AFP.

"We're happy and moved to see the pope, even if we're outside, and to feel this connection between each other," the 19-year-old added.

Julie, a 50-year-old who manages a business in France, said the pope was a "very humble man, I think he's capable of offering a message of peace and trying to unite people and ease tensions".