The Vatican has said that Pope Francis, who has been hospitalised and in critical condition with pneumonia in both lungs, was showing a “slight improvement” The Vatican, however, cautioned that doctors would not offer a prognosis.

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.

Pope Francis has the onset of double pneumonia, the Vatican said on Tuesday, complicating treatment for the 88-year pontiff and indicating a further deterioration in his fragile health.