Pope Francis' condition remained stable on Tuesday, and his prognosis remains reserved, according to the Vatican. The pope had needed medical intervention amid two episodes of "acute respiratory failure" on Monday,

Pope Francis, batting double pneumonia in hospital, remained stable throughout the day on Tuesday and did not have any new respiratory crises, the Vatican said.

In a late update, the Vatican said the episodes were caused by a 'significant accumulation' of mucus in his lungs and bronchial spasms.