Pope Francis was in critical condition on Saturday night after having a long “asthmatic respiratory crisis” that required “high flows of oxygen” as well as a blood transfusion, the Vatican said, adding to concerns about the health of the 88-year-old pontiff.

The announcement indicated that Francis’ medical condition had become more complicated since an update from his doctors on Friday evening, when he was also said to be in critical condition. “The pope is not out of danger,” the Vatican said on Saturday evening.

The pope was hospitalized on Feb. 14 with a respiratory tract infection that developed into pneumonia in both lungs.

But the Vatican said on Saturday that Francis was alert and sitting up in an armchair, “though he was in more pain than yesterday.”

The blood transfusion was necessary because tests showed low platelet counts associated with anemia, the Vatican said.