Pope Francis suffered “two episodes of acute respiratory failure” Monday, the Vatican announced.

“Today, the Holy Father presented two episodes of acute respiratory failure, caused by significant accumulation of endobronchial mucus and consequent bronchospasm,” according to the Vatican. “Two bronchoscopies were therefore performed requiring aspiration of abundant secretions.”

“In the afternoon, non-invasive mechanical ventilation was resumed,” it added in a statement. “The Holy Father has always remained vigilant, oriented and collaborative. The prognosis remains guarded.”

Broncospasm is defined by the American Academy of Allergy, Asthma & Immunology as “a contraction of the muscular coat of the bronchial tubes” that “results in a narrowing and obstruction of the breathing airways.”

Catholic faithful attend a nightly rosary prayer for the health of Pope Francis in St. Peter’s Square at the Vatican on Sunday, March 2. (AP/Mosa’ab Elshamy)

Doctors said the pope spent all day Sunday without using the noninvasive mechanical ventilation mask that pumps oxygen into his lungs that he used after a breathing crisis on Friday. 

“I would like to thank you for your prayers, which rise up to the Lord from the hearts of so many faithful from many parts of the world,” Pope Francis wrote on his X account on Sunday. 

Pope Francis was admitted to Rome’s Gemelli Hospital on Feb. 14. (Tiziana Fabi/Pool/AFP/Getty)

“I feel all your affection and closeness and, at this particular time, I feel as if I am ‘carried’ and supported by all God’s people,” he added.

Fox News’ Melissa Chrise and Landon Mion contributed to this report.