The health of Pope Francis, who has been hospitalized for over a week with pneumonia, worsened on Saturday, raising fears that the pontiff might not survive his struggle with respiratory infections.

Doctors on Friday said the 88-year-old Francis is "not out of danger" ​and that the main threat facing him would be the onset of sepsis.

Pope Francis is in critical condition and his "prognosis remains guarded" as he experienced a respiratory crisis Saturday morning requiring oxygen and blood transfusions, the Vatican said Saturday night.