The Vatican carried on with its Holy Year celebrations without the pope on Saturday, as Pope Francis battled pneumonia and a complex respiratory infection that doctors say remains touch and go and will keep him in hospital for at least another week.

Pope Francis was in critical condition Saturday after he suffered a long asthmatic respiratory crisis that required high flows of oxygen, the Vatican said.

The Vatican on Monday announced the start of nighttime prayers for the health of Pope Francis in St. Peter's Square, and invited Romans and others to join in, as the 88-year-old pontiff battled a complex lung infection and complications.