ROME and LONDON -- Pope Francis suffered two episodes of "acute respiratory failure" on Monday, the Vatican said. The episodes were caused by a "significant accumulation of endobronchial mucus and consequent bronchospasm," the Vatican's press office said in a brief statement.

Pope Francis on Monday suffered two attacks of "acute respiratory insufficiency," the Vatican said, as the 88-year-old continues his health fight.

Catholic faithful gathered in St Peter's Square once again on Monday night to pray for Pope Francis' health as the Vatican announced he had suffered two new acute respiratory crises.