ROME — The Vatican announced Sunday that Pope Francis had been admitted to a hospital in Rome for colon surgery, the first significant health challenge in a pontificate that has lasted more than eight years and shifted the priorities and direction of the Roman Catholic Church.

Matteo Bruni, a Vatican spokesman, said in a statement that Francis, 84, had been taken to the Gemelli hospital in the Italian capital.

The Vatican announced later that Francis “reacted well” to the intestinal surgery.

In a statement late Sunday, Bruni said Francis had general anesthesia during the surgery necessitated by a stenosis, or narrowing, of the sigmoid portion of the large intestine.

The surgery was performed by Dr. Sergio Alfieri, who heads the hospital’s complex operational unit for digestive surgery, the Vatican said.

It was the first time that Francis has been admitted to a hospital since becoming pope in 2013 and comes at a time of tension in the church, with the Vatican this week indicting officials on charges of financial crimes, American bishops last month essentially disregarding Rome’s appeal to hold off on a politically fraught document about the Eucharist, and many in the church confused by Francis’ new warm words to LGBTQ Catholics even as his church continues to hold a hard line.

Through it all, Francis, whose pontificate has been built around his personal style and expressed desire to reinvigorate the church, has stayed put and kept the power center with him in the Vatican. Unlike his predecessors, he has never left the Vatican for the cooler papal residence in Castel Gandolfo, near Rome, during the summer. He normally slows down his schedule in July.

Bruni recently announced that the weekly general audiences held on Wednesdays would be suspended for the month of July, and begin again Aug. 4. He said the Sunday Angelus prayer and blessing would continue throughout the summer.

In remarks Sunday, Francis made no mention of the operation. But he did say in his weekly blessing June 27, “Pray in a special way: The pope needs your prayers.”

Until now, the pope’s health has not been cause for much concern.

More than 60 years ago, he had an upper lobe of his lung removed as a result of complications from tuberculosis. And in recent years, his breathing has seemed labored during speeches. But Francis has maintained an often exhausting schedule during his foreign trips, most recently to Iraq in March.

He has, however, clearly slowed, in part because he has sciatica, a condition that causes leg and back pain, and he has missed some engagements. This past year, he missed New Year’s Eve and Day services because of a flare-up.

The Vatican’s characterization of the procedure as scheduled — not urgent — was a good sign, according to Dr. Anne Peery, a gastroenterologist at the University of North Carolina in Chapel Hill.

Francis suffers from diverticulitis, a condition in the sigmoid colon in which sac-like bulges on the colon walls become repeatedly inflamed or infected and can warrant surgical intervention, according to Dr. Feza Remzi, director of the Inflammatory Bowel Disease Center at NYU Langone Health.

Earlier, Francis looked serene while addressing people at St. Peter’s Square for the weekly Angelus prayer and blessing.

The Associated Press contributed.