Pope Francis "rested well throughout the night" in the hospital, the Vatican says, and even met with Vatican officials to sign several documents linked to sainthood designations on Monday.

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.

The Vatican on Monday announced the start of nighttime prayers for the health of Pope Francis in St. Peter's Square, and invited Romans and others to join in, as the 88-year-old pontiff battled a complex lung infection and complications.