Pope Francis's respiratory tract infection showed signs of improvement on Saturday, but the hospitalized pontiff will not lead his weekly Angelus prayer following Sunday mass, the Vatican said Saturday.

The 88-year-old pontiff was admitted Friday to Rome's Gemelli hospital for treatment for what the Vatican called "ongoing bronchitis", while planned audiences for Saturday and Sunday were cancelled. 

"Pope Francis rested all night. He has not shown any fever episodes," said the Vatican in a statement early Saturday evening, saying tests confirmed a diagnosis of "respiratory tract infection".

"Today's laboratory tests show improvement in some values," it added. 

Doctors had prescribed "absolute rest" so Francis will not lead Sunday's Angelus prayer but instead send a text for its publication, the Vatican said. 

"Pope Francis has been updated on the many messages of closeness and affection received and expresses his gratitude, asking at the same time to continue praying for him," said the Vatican. 

Earlier on Saturday morning, Francis took Communion and then "alternated rest with prayer and reading", it said. 

Ahead of his hospitalisation, Francis had been seen breathless while reading speeches aloud and had delegated officials to read them on his behalf. 

At the hospital -- where Francis is occupying a special suite just for popes with its own chapel -- family members of other patients wished the pontiff well.

"I wish the Pope a speedy recovery because we need him, we need a guide," said retired Rome resident Pasqualino Ilari. 

"He has proven to be a wise and reliable leader and I hope he will be discharged as soon as possible." 

The Argentine pontiff, who had part of one of his lungs removed as a young man, has increasingly been plagued by health issues in recent years, despite continuing to maintain a busy schedule.

He was taken to hospital with bronchitis in March 2023 and suffered from the illness again months later.

The pope had hernia surgery in June 2023 and in 2021 underwent an operation for a type of diverticulitis, an inflammation of pockets that develop in the lining of the intestine.

Since 2022, the pope has relied on a wheelchair due to persistent knee pain and a cane during rare moments standing up.