Pope Francis remains in critical condition, according to the Vatican, with blood tests showing mild signs of kidney failure “which is currently under control,” the Vatican said Sunday, as the 88-year-old pontiff battles pneumonia in both his lungs.

The Vatican said Francis hadn't had any more respiratory crises since Saturday night but was still receiving high flows of supplemental oxygen.

The kidney ailment appears to be in an early stage, the Vatican said, adding that the pontiff is still receiving high flows of oxygen for his respiratory illness.