Pope Francis acknowledged being fragile and "facing a period of trial", as he thanked well-wishers Sunday for prayers in a message from hospital, where he has been slowly recovering from pneumonia.

The pope was admitted to Rome's Gemelli hospital on Feb. 14 with a severe respiratory infection that has required evolving treatment.

The photo is said to have been taken Sunday when Francis was co-celebrating Mass in the chapel of his hospital suite where he has been battling a health crisis.