Ailing pope 'rested well' amid improvement: Vatican

The Argentine pontiff was admitted to Rome's Gemelli hospital on February 14 with breathing difficulties and bronchitis but his condition has subsequently worsened and Catholic faithful around the world have been praying for his recovery.

"The Pope rested well, all night long," said the Vatican in a morning update on the 12th day of the pope's hospital stay.

The Holy See issued a more hopeful update Monday evening, saying that the pope's "critical clinical conditions... demonstrate a slight improvement".

It said Francis had experienced no more respiratory attacks -- as he had suffered on Saturday, requiring "high-flow oxygen" -- and some lab tests had improved.

But the pope remains "a fragile patient," as his doctor Luigi Carbone stated Friday, and his medical team have cautioned that it will take time for his drug treatments to show a positive effect.

"Considering the complexity of the clinical picture," his doctors have declined to "decide on the prognosis," the Vatican said Monday.

Francis, who is staying in a special papal suite on the 10th floor of the hospital, has continued to do some work and has moved from his bed to an armchair, while receiving the Eucharist in the morning.