It is unclear how long Pope Francis will stay in hospital, according to a Holy See spokesperson, after he was admitted on Friday with a respiratory tract infection.

Pope Francis was hospitalized Friday to treat a weeklong bout of bronchitis and undergo some necessary diagnostic tests, the Vatican said, confirming the latest issues with the 88-year-old's pontiff's health .

Pope Francis was hospitalized Friday for the fourth time since being elected in 2013, after he was diagnosed with bronchitis last week. Francis had part of one lung removed as a young man and has recurring bouts of bronchitis,