Pope Francis is responding well to treatment for acute respiratory failure, marking the first notable improvement since his hospitalization nearly three weeks ago, a Vatican source told CNN.

According to a statement from the Vatican press office on Saturday, the 87-year-old pontiff has shown a “good response to therapy” and a “gradual, slight improvement” since experiencing severe breathing difficulties on Monday.

The improvement is attributed to better “gas exchange” in the lungs and increased blood oxygenation. However, Vatican officials caution that the risk of another respiratory crisis remains, and his prognosis remains uncertain.

Pope Francis continues to receive high-flow oxygen therapy during the day and non-invasive ventilation at night, the Vatican press office reported.

Despite his health struggles, the pope has maintained his spiritual routine. On Saturday, he prayed in a chapel and later rested while engaging in work activities. The Vatican also confirmed that Sunday’s Angelus prayer will be released in written form.

Starting Monday, Pope Francis is expected to take part in the traditional Lenten “spiritual exercises” from his hospital room, demonstrating his commitment to religious observances.

Since Monday’s health scare, the pope’s condition has remained stable as he undergoes respiratory and motor physiotherapy. In a pre-recorded message released on Thursday, he expressed gratitude to supporters for their prayers.