Pope Francis, hospitalized for more than two weeks with pneumonia in both lungs, suffered two acute respiratory failures, requiring intervention, the Vatican says.

Pope Francis had an "isolated breathing crisis" in hospital on Friday, the Vatican said, in a setback as the 88-year-old pontiff battles double pneumonia.

Pope Francis is in stable condition and does not have a fever, the Vatican said on Sunday, days after he suffered from a sudden respiratory episode in hospital where he has been battling double pneumonia.