The Vatican reported Friday that he experienced sudden breathing problems that required “non-invasive mechanical ventilation” but that he remained “alert.”

The Vatican said Francis, 88, who has been hospitalized for pneumonia, was responding well to treatment and that it was too soon to say how serious the incident was.

The health of Pope Francis remains unclear as the faithful have gathered in St. Peter’s Square nightly to pray for his recovery. The 88-year-old pontiff was hospitalized almost two weeks ago, suffering from double pneumonia and mild renal insufficiency.

The Vatican has set in motion nightly prayers for Pope Francis in the hope that he might recover and get back to leading the Catholic Church.

Despite his hospitalization, the pope has maintained a degree of governance and authorized the appointment of four new bishops.

Pope Francis suffered a bronchial spasm on Friday that resulted in him breathing in vomit, requiring non-invasive mechanical ventilation, the Vatican said in relaying a setback in his two-week long battle against double pneumonia.

Hundreds gather to pray for Pope Francis, who is showing slight improvement in tests Thursday, according to the Vatican.

Thousands of people gathered in St. Peter’s Square to pray for an ailing Pope Francis, expressing sorrow for his suffering, hope for his recovery and gratitude for his efforts to steer the Catholic Ch

From Vatican City to the Queen City, prayers are being said for the recovery of Pope Francis, who is currently in critical but stable condition after being diagnosed with double pneumonia.