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.

Monday marks Pope Francis’ 10th day in the hospital, making this equal to the longest hospitalization of his papacy.

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.