Pope Francis is being treated with supplemental oxygen to assist him with breathing, the Vatican said Tuesday, a day after he suffered two episodes of acute respiratory failure. Francis is currently receiving oxygen again via a nasal tube,

Pope Francis suffered two episodes of acute respiratory failure Monday, the Vatican said, a fresh setback in the worst health crisis of his papacy.

This was the pope's "third serious downturn" since he was admitted to Gemelli Polyclinic hospital with a complex respiratory infection on Feb. 14, the BBC said. The Vatican said laboratory tests suggested the mucus was a response to Francis' original pneumonia, not a new infection.