Pope Francis is being treated for a “complex clinical situation” and will remain in hospital for as long as necessary, the Vatican has said.
The 88-year-old was admitted to Rome’s Gemelli hospital on Friday to undergo treatment and tests for bronchitis.
In an update on Monday, the Vatican said the pontiff has a “polymicrobial infection” of his respiratory tract, which has required a change in his treatment.
Before his admission last week, the Pope had bronchitis symptoms for several days and had delegated officials to read prepared speeches at events.
Vatican spokesman Matteo Bruni told reporters on Monday that the pontiff was in good spirits.
A short statement on his condition said: “All tests carried out to date are indicative of a complex clinical picture that will require appropriate hospitalisation.”
The pontiff’s weekly general audience, which is usually held each Wednesday, has been cancelled for this week, the statement added.
A further update on the Pope’s condition would be released later on Monday, Mr Bruni added.
Over the weekend, the Vatican said the Pope was stable and that he’d been told to have “complete rest” to aid his recovery.
The Pope was unable to deliver his regular weekly prayer on Sunday in St Peter’s Square or lead a special mass for artists to mark the Catholic Church’s Jubilee Year.
Last Wednesday, the Pope asked a priest to read part of his speech because of his difficulties with illness.
He also held meetings at his Vatican residence last week in an attempt to rest and recover.
The Argentine pontiff has spent nearly 12 years as leader of the Roman Catholic Church.
He previously spent three nights at the same hospital in March 2023 for bronchitis treatment.
In December the same year, he was forced to cancel his trip to the United Arab Emirates for the COP28 climate summit because of another bout of illness.
He has suffered a number of health issues throughout his life, including having part of one of his lungs removed at age 21.