Pope Francis remains in critical but stable condition after undergoing a CT scan on Tuesday, the Vatican announced.

Vatican officials say the pope, 88, returned to work in the evening, making a phone call to the parish priest of Gaza. He also expressed gratitude for "all the people of God who have gathered to pray for his health in recent days."

"The Holy Father’s condition remains critical, but stable. No acute respiratory episodes have occurred and the hemodynamic parameters continue to be stable," the Vatican said in a statement, translated from Italian.

"In the evening, he underwent a scheduled control CT scan for radiological monitoring of bilateral pneumonia. The prognosis remains reserved. In the morning, after receiving the Eucharist, he resumed work," the statement continued.

POPE FRANCIS SHARES WRITTEN MESSAGE WHILE CONTINUING HOSPITALIZATION

Francis was admitted to the hospital on Feb. 14 after a week-long bout of bronchitis worsened. Doctors first diagnosed the complex viral, bacterial and fungal respiratory tract infection and subsequently the onset of pneumonia in both lungs.

Late Sunday, doctors said blood tests revealed "early, slight kidney insufficiency" but that it remained under control. The doctors said Francis remained in critical condition but had not experienced any further respiratory crises since Saturday evening.

POPE FRANCIS HAD PEACEFUL NIGHT'S REST AT HOSPITAL FOLLOWING RESPIRATORY CRISIS, VATICAN SAYS

Francis, who had part of one lung removed when he was younger, was receiving high flows of supplemental oxygen, and received two blood transfusions on Sunday to increase hemoglobin levels. Doctors said his prognosis was guarded.

The pope was alert and responsive on Sunday and attended Mass.

Francis' condition is touch-and-go, given his age, fragility and pre-existing lung disease, doctors said. The main threat to Francis, doctors warned, is sepsis, a serious infection of the blood that can arise as a complication of pneumonia.

Tuesday is Francis' 11th day in the hospital, exceeding the longest hospitalization of his papacy. He spent 10 days at Gemelli Hospital in 2021 after he had 13 inches of his colon removed.

Cardinal Timothy Dolan said Sunday in New York that the Catholic faithful were united "at the bedside of a dying father," an acknowledgment of Francis' short time left that church leaders in Rome have not said publicly.

Fox News' Landon Mion contributed to this report.