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.

Pope Francis was found to have pneumonia in both his lungs Tuesday and his condition remains "complex," the Vatican said in a health update on the 88-year-old pontiff who was hospitalized last week. The big picture: The pope was admitted to Rome's Agostino Gemelli Hospital on Friday with bronchitis symptoms and his treatment was changed after doctors found he had a polymicrobial infection of the respiratory tract.