Pope Francis remained in critical condition Sunday and blood tests showed early kidney failure but he remains alert, responsive and attended Mass, the Vatican said, as the 88-year-old pontiff battles pneumonia and a complex lung infection.

In a late update, the Vatican said Francis hadn’t had any more respiratory crises since Saturday night but was still receiving high flows of supplemental oxygen.

Some blood tests showed “initial, mild, kidney failure,” but doctors said it was under control.

“The complexity of the clinical picture, and the necessary wait for drug therapies to provide some feedback, dictate that the prognosis remains guarded,” Francis’ doctors concluded.

Prayers for Francis, meanwhile, poured in from around the world, from his native Argentina to the seat of Sunni Islam in Cairo to schoolchildren in Rome.

In New York, Cardinal Timothy Dolan admitted what church leaders in Rome weren’t saying publicly: that the Catholic faithful were united “at the bedside of a dying father.”

“As our Holy Father Pope Francis is in very, very fragile health, and probably close to death,” Dolan said in his homily from the pulpit of St. Patrick’s Cathedral, though he later told reporters he hoped and prayed that Francis would “bounce back.”

Doctors have said Francis’ condition is touch-and-go, given his age, fragility and pre-existing lung disease.

His condition has revived speculation about what might happen if he becomes unconscious or otherwise incapacitated, and whether he might resign.