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 press office for the Vatican said Sunday that Pope Francis was able to rest overnight as he slowly recovers from double pneumonia after initially being hospitalized for bronchitis.

The Vatican described his condition as critical for the first time on Saturday, reporting that the 88-year-old Francis needed supplemental oxygen and blood transfusions after a "prolonged asthma-like respiratory crisis.