The Vatican says that Pope Francis has suffered two new episodes of acute respiratory crises and has been put back on noninvasive mechanical ventilation.

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.