The pontiff's condition is touch-and-go, given his age, fragility and pre-existing lung disease, according to doctors.

Pope Francis rested overnight in the hospital, the Vatican said on Sunday. "The night passed peacefully. The Pope rested," the Holy See said in a short statement. The 88-year-old pontiff underwent another round of clinical tests on Sunday morning,

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