Pope Leo has cancelled all planned public events until Tuesday 20 October, ahead of surgery to remove a small growth on one of his lungs.
The 71-year-old pontiff announced on Sunday that doctors had discovered a "well-defined lung nodule, detected at a very early stage and clearly localised".
He will enter Rome's Gemelli hospital on Tuesday (13 October) morning, but it is not yet clear when the operation will take place.
This morning, the Pope met with visiting bishops from Argentina, Nicaragua and the US, among others.
In a meeting at the Vatican with members of a Rome-based charity group on Monday, Pope Leo spoke in a strong, clear voice as he thanked them for their work.
Pope Leo XIV, who is originally from the US, has no previously known health problems and is known to be physically active, with weekly tennis games and swimming at the papal summer retreat in Castel Gandolfo.
The surgery will not affect his scheduled trip to Uruguay, Argentina and Peru next month, Sky News understands.
The Vatican previously said that "the post-operation recovery will be around one week".
Pope Leo announced the diagnosis during his weekly Sunday noon blessing from St Peter's Square in Vatican City.
He told pilgrims: "The doctors consider it appropriate to intervene, and so, following their advice, I have decided to undergo surgery to have it removed.
"I thank you and entrust myself to your prayers."
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His predecessor, the late Pope Francis, died at the age of 88 and was increasingly frail in his later years.
Reacting to the news, Italian Prime Minister Georgia Meloni said: "I would like to express to the Holy Father my personal closeness and that of the Italian Government as he faces the challenge that lies ahead in the coming days.
"The calm and serenity with which he spoke about it during today's Angelus are reassuring. I am certain that the Italian people, too, will offer him their unwavering support and affection."
(c) Sky News 2026: Pope Leo cancels all public events ahead of lung surgery
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