VATICAN CITY - Pope Francis spent the night in hospital in Rome, where the 86-year-old will continue receiving treatment on Thursday for what the Vatican has said is a respiratory infection.
A spokesman initially said the pontiff had been admitted to Rome's Gemelli hospital Wednesday for previously scheduled tests -- but in a later statement revealed that Francis had complained in previous days of "breathing difficulties."
Tests showed a respiratory infection that was not Covid-19, requiring "a few days of appropriate hospital medical treatment", Vatican spokesman Matteo Bruni said.
A Vatican source told AFP that the pope's appointments for Thursday morning had been cancelled.
Francis' admission -- which prompted a few dozen journalists to camp outside the hospital Wednesday night -- came a few weeks after marking a decade as head of the Catholic Church.
It also comes just ahead of Holy Week and Easter, Christianity's most important holiday.
Over the past year Francis has suffered from chronic knee pain that has required him to use a wheelchair.
His postponement last year of a scheduled trip to Africa and various events at home fueled intense speculation about his health, and in a July 2022 interview he acknowledged that he needed to slow down.
At his weekly audience at the Vatican on Wednesday morning, the pope appeared in good spirits, smiling as he greeted the faithful from his "popemobile".
But he was seen visibly grimacing as he was helped getting into the vehicle.
Francis was admitted in July 2021 to the same Rome hospital for 10 days for an operation on his colon after suffering from a type of diverticulitis, an inflammation of pockets that develop in the lining of the intestine.
In an interview in January, Francis said the diverticulitis had returned.
Francis has repeatedly said, most recently in February, that he would consider stepping down if his health required it, following the example of his predecessor Benedict XVI.
He has cautioned, however, that papal resignations should not be the norm, and said in an interview last month that the idea was currently not "on my agenda".
Benedict, who died on December 31, shocked the world in 2013 by becoming the first pope since the Middle Ages to resign.
In 1957, at age 21, Francis had part of one of his lungs removed, but he has said he made a full recovery.
At age 86, Francis keeps a busy schedule at home and continues to travel internationally.
Earlier this year, he visited South Sudan and the Democratic Republic of Congo, drawing huge crowds.
Next month, he is due to visit Hungary and meet Prime Minister Viktor Orban.
In the past decade, Francis has sought to forge an image of a more open, compassionate Church, although has faced internal opposition, particularly from conservatives.