The pope is undergoing hospital treatment for bilateral pneumonia. His prognosis is being kept closely guarded.

Pope Francis, who has been struggling to overcome double pneumonia for almost three weeks, had a restful night in hospital, the Vatican said on Wednesday. The 88-year-old pope was admitted to Rome's Gemelli hospital on February 14 with a severe respiratory infection that has required continuously evolving treatment.

St Peter's Square is bustling, but behind the Vatican's walls, activities have slowed as the Catholic Church grapples with the uncertainty caused by the absence of Pope Francis. Tourists take photos in the spring sunshine and streams of pilgrims marking the Catholic "Holy Year" head to the basilica,