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.

Pope Francis remained in critical but stable condition Tuesday, with his blood parameters remaining stable as he works from the hospital while battling double pneumonia, the Vatican said. The Vatican's evening update said the 88-year-old pope underwent a follow-up CAT scan in Tuesday evening to check the lung infection.

On Monday evening, doctors said Pope Francis remained in critical condition with double pneumonia but reported a "slight improvement" in some laboratory results.