Francis, who has been in Rome's Gemelli Hospital since February 14, is again receiving "non-invasive, mechanical ventilation" to help with his breathing.

The crisis was a new setback in the Pope's fight to recover from a complicated respiratory infection, which has lasted more than two weeks. Pope Francis has chronic lung disease and had part of one lung removed as a young man.

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