The faithful gathered at St. Peter's to remember Pope Francis after his death
The faithful gathered at St. Peter's to remember Pope Francis after his death AFP

A hush reigned over the normally boisterous St Peter's Square on Monday as the faithful and the curious alike gathered at the seat of Catholicism to mark the death of Pope Francis.

Catholic priests and nuns in groups of threes of fours bowed their heads to pray, twirling their rosaries under the midday sun just hours after the Vatican announced the 88-year-old pontiff's passing.

Even the groups of tourists, who continued to enter the massive St Peter's Basilica, appeared quiet and downcast.

"He was the voice of the smallest, the weakest. And up until yesterday he was asking for peace in the world," Venezuelan seminarian Riccardo Vielma, 31, told AFP.

In the grand, pillar-lined plaza, the yellow and red tulips remained as did the rows of the seats set up for Sunday's Easter mass, where Francis had saluted the public for the last time.

"We're really all stunned because yesterday he was here, he did a full tour of the square (in his popemobile)," said Royben Noris, also from Venezuela.

"It was such a great joy for everyone to see him again at St Peter's Square," Noris added.

The joyful atmosphere from the previous day has turned sombre, as people made the sign of the cross, wiped tears from their eyes or huddled with their loved ones.

A group of Franciscan friars, recognisable in their brown robes and sandals, leaned against a railing staring at the basilica while a group of young people stood in a circle nearby, reciting an audible prayer.

Photographers and television cameras began setting up at the back of the square, in a preview of the heavy media interest to come as the Church embarks on the process to choose a new pope.

Irish tourist Naoimh Kelly, 44, said she and her son headed directly for St Peter's after hearing the news in their hotel.

"He was the same as everyone else, he was always about the people, he wasn't fancy. He was a real humanitarian," she said.

"I'm from Ireland and the Church has a bad name. But he changed the way people thought. It's a shame."

An Italian woman, who gave her name as Nunzia, 63, said she often came to St Peter's on Sunday to watch the pope preside over mass and give his traditional Angelus prayer.

"People really loved him. Catholics and non-Catholics alike," she said.

"Mamma mia, it's really hit me," she told AFP. "The only thing I could do was to come by here for a moment of reflection."

The Argentine pontiff, leader of the Catholic Church since March 2013, spent 38 days being treated for double pneumonia at Rome's Gemelli hospital before seeming to recover, leaving the facility on March 23.