Pope Francis remained in critical condition Monday but showed slight improvement in laboratory tests and resumed some work, the Vatican said, including calling a parish in Gaza City that he has kept in touch with since the war there began.

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.

The announcement on Saturday evening indicated that Francis’ medical condition had become more complicated since an update from his doctors on Friday.