Pope Francis has been told to stay in hospital for a few days for treatment after doctors diagnosed a respiratory infection, the Vatican announced on Wednesday.

"Pope Francis is touched by the many messages received and expresses his gratitude for the closeness and prayer," the Vatican said.

On Wednesday morning, Francis held his weekly general audience on St. Peter's Square in front of thousands of worshippers.

The 86-year-old pontiff was taken to Gemelli University Hospital in Rome in the afternoon for what was initially called a scheduled visit. But soon after, his appointments for Thursday were called off.

Reporters and press photographers were posted outside the hospital by late Wednesday. 

The Vatican did not elaborate on whether the pope would be back in time to celebrate the busy Holy Week events that are due to begin this weekend with Palm Sunday.

What do we know about the pope's health?

The pope had been complaining of breathing difficulties in the past few days. Vatican spokesperson Matteo Bruni said that he did not have COVID-19.

Francis got through the worst phases of the coronavirus pandemic without any public announcements of having contracted the virus. 

The pope, who usually speaks in a whisper, earlier in his life had part of one lung removed due to a respiratory infection. He has said he resisted undergoing knee surgery because he didn't respond well to general anesthesia during a 2021 intestinal surgery.

Francis had to cancel or postpone activities several times last year due to knee pain. In a 2022 interview, he admitted that he needed to slow down because of his health. 

The Argentine-born Jorge Maria Bergoglio this month marked 10 years as head of the Catholic Church.

He led his predecessor Benedict XVI's funeral this January, after the first living handover of papal power in centuries.

fb, ab/msh (dpa, Reuters)