VATICAN CITY, Holy See (AFP) – Pope Leo XIV made a surprise appearance in a crowd of 120,000 young Catholics who gathered on Tuesday in Rome for the Vatican’s Jubilee of Youth — an event that takes place every 25 years.

The week-long event is taking place just over two months after Leo XIV became the head of the Catholic Church and the first American pope.

Since Monday, groups of pilgrims — chanting and draped in flags of their countries — have flooded the streets of Italy’s capital and the corners of the Vatican City.

The Vatican had last week said it expected some half a million people from more than 150 countries to take part, with this year’s events dedicated to faith and culture.

Some 120,000 people attended the opening mass at St Peter’s Basilica Tuesday evening, according to the Vatican, where the Pope said he had a special welcome for people from regions affected by war, naming Ukraine and Palestine.

Afterwards, he made a surprise appearance in the crowd aboard his “Popemobile”.

The week will culminate with a giant mass led by Pope Leo on Sunday.

The Jubilee of Youth is aimed at people aged between 18 and 35.

Pilgrims told AFP the subjects they most wanted to discuss at the events were wars, climate change, social inequalities and the dangers linked to artificial intellegence (AI).

“The most important topic for me is war. Everyone is talking about it, thinking about it, and we want to know what the pope thinks about it and what he expects from us,” said 25-year-old Tiago Santos from Portugal.

The event is taking place after almost two years of Israeli bombardment of Gaza, which has left tens of thousands of Palestinians dead and United Nation (UN) groups warning of starvation in the blockaded territory.

Thousands have also been killed in Ukraine since Russia’s 2022 invasion, with Moscow continuing deadly attacks despite Western pressure to end its campaign.

Teophanie Nasta, a 26-year-old from Lebanon travelling overseas for the first time, said that despite the conflicts in the Middle East she was filled with “faith in humanity by seeing so many young people” gathered for the church.

In an unprecedented move, the Vatican dedicated a series of events to Catholic influencers — a sign of growing importance of social media for the church.

Speaking to them on Tuesday morning, Pope Leo warned against the dangers of undermining “human dignity” in the AI era.