Pope Francis experienced “two episodes of acute respiratory failure,” the Vatican said Monday, marking the latest in a series of medical crises the 88-year-old pontiff has endured since he was first hospitalized last month.

Pope Francis is alert after suffering two episodes of "acute respiratory failure" on Monday afternoon, the Vatican has said. Doctors were forced to intervene to clear mucus from the Pope's lungs, an update from the Holy See said, though it said he was alert throughout.