Pope Francis was admitted to hospital on Wednesday morning to undergo an operation, prompting renewed concerns about the state of his health.
The head of the Catholic Church visited the Gemelli Hospital in Rome on Tuesday for what was described by the Vatican as routine checks.
But he returned to the hospital after his weekly general audience in St Peter’s Square on Wednesday morning.
He will undergo intestinal surgery, two years after he had 13 inches of his colon removed because of an inflammation and narrowing of the large intestine.
Pope Francis, 86, will be put under general anaesthesia for the operation and will have to stay in hospital for several days to recover.
The Vatican said he will undergo a “laparotomy [open abdominal surgery] and abdominal wall plastic surgery with prosthesis”.
The aim is to try to resolve “recurrent, painful and worsening” constriction of the intestine.
“The stay at the health facility will last several days to allow for the normal post-operative course and full functional recovery,” the Holy See said in a statement.
The Pope suffers from diverticulitis, a condition that can infect or inflame the colon.
He revealed earlier this year that the condition had returned, but that he was not overly concerned. The Jesuit pontiff has suffered from a range of health issues in recent years.
In March, he spent several days in hospital owing to a respiratory infection. He had complained of breathing difficulties.
In late May, he had to cancel some engagements as a result of a fever.