Rushdie has lived under an Iranian death sentence since 1989.

The author Salman Rushdie, who spent years in hiding and under police protection after Iranian officials called for his execution, was attacked and stabbed in the neck on Friday while onstage in Chautauqua, near Lake Erie in western New York, the state police said.

The attack, which shook the literary world, happened at about 11 a.m., shortly after Mr. Rushdie, 75, took the stage for a lecture at the Chautauqua Institution, a community that offers arts and literary programming during the summer.

Mr. Rushdie was taken by helicopter to a local hospital, the state police said in a statement. His condition is not yet known. His agent, Andrew Wylie, said in an email Friday afternoon that Mr. Rushdie was undergoing surgery.

It was not clear what motivated the attacker.

Linda Abrams, from the Buffalo area, who was sitting on the front row, said the assailant kept trying to attack Mr. Rushdie even after he was restrained. “It took like five men to pull him away and he was still stabbing,” she said. “He was just furious, furious. Like intensely strong and just fast.”

Rita Landman, an endocrinologist who was in the audience, said that Mr. Rushdie had multiple stab wounds, including one to the right side of his neck, and that there was a pool of blood under his body. But she said he appeared to be alive. “People were saying, ‘He has a pulse, he has a pulse, he has a pulse,’” Ms. Landman said.

The state police said that the interviewer at the event had also “suffered a minor head injury” but did not identify him. The Chautauqua Institution said on Twitter that it was asking for “your prayers for Salman Rushdie and Henry Reese.” Mr. Reese, the moderator of the morning’s discussion, co-founded a program for exiled writers.

Credit…Joshua Goodman/Associated Press

Suzanne Nossel, the chief executive officer of PEN America, which promotes free expression, said that “we can think of no comparable incident of a public attack on a literary writer on American soil.”

“Just hours before the attack, on Friday morning, Salman had emailed me to help with placements for Ukrainian writers in need of safe refuge from the grave perils they face,” she said in a statement. “Salman Rushdie has been targeted for his words for decades but has never flinched nor faltered.”

Mr. Rushdie spent about 10 years under police protection, living in hiding after Ayatollah Ruhollah Khomeini, the Supreme Leader of Iran after the 1979 Iranian Revolution, called for his execution in 1989 because his novel “The Satanic Verses” was considered offensive to Islam. The book was banned in India, where he was born, and he was barred from the country for more than a decade.

Mr. Rushdie had just come onstage to deliver the morning lecture at the 4,000 seat amphitheater of Chautauqua Institution, a gated community that features arts and literary programming each summer, when he was attacked, witnesses said.

He was there for a discussion about the United States as a safe haven for exiled writers and other artists who are under the threat of persecution. The conversation was scheduled to be moderated by Mr. Reese, the co-founder of a Pittsburgh nonprofit, City of Asylum, which is a residency program for exiled writers.

Mr. Rushdie had just sat down and was being introduced when the assailant rushed the stage and assaulted him.

“I could just see his fists sort of pounding on Salman,” one witness, Bill Vasu, 72, said.

A number of people rushed to Mr. Rushdie’s aid, Mr. Vasu said, and quickly pinned the attacker to the ground.

A trooper assigned to the event took the assailant into custody, the police said. The person interviewing Mr. Rushdie also suffered a minor head injury.

Governor Kathy Hochul of New York said on Twitter that she had directed the State Police to assist in the investigation and that “Our thoughts are with Salman & his loved ones following this horrific event.”

Several witnesses said the attacker was able to reach Mr. Rushdie easily, running onstage and approaching him from behind. “There was just one attacker,” said Elisabeth Healey, 75, who was in the audience. “He was dressed in black. He had a loose black garment on. He ran with lightning speed over to him.”

“It was very frightening and it gave me a pit in my stomach,” said Jane Bulette, 68, who has been coming for more than a decade. “How could they not have blocked off the stairs to the stage?”

“There was a huge security lapse,” said Ms. Bulette’s husband, John, 85, who witnessed the attack. “That somebody could get that close without any intervention was frightening.”

Kyle Doershuk, 20, was working as an usher at the amphitheater at the time of the attack. He said he was about 15 feet away from the assailant as he began to rush the stage with a knife, after dropping a backpack. By the time Mr. Doershuk understood something was going wrong, the attack had begun.

Mr. Doershuk said security at the Institution is lax and that there did not appear to be any additional measures in place for Mr. Rushdie’s visit. “It’s very open, it’s very accessible, it’s a very relaxed environment,” he said. “In my opinion something like this was just waiting to happen.”

Another eyewitness, Anita Ayerbe, 57, said she had seen the attacker on the grounds of the Institution on Thursday afternoon near the amphitheater, and that he was able to access the stage easily.

“The amphitheater is a soft target,” Ms. Ayerbe said. “There was no obvious security at the venue and he ran up unimpeded. The cops were not the first ones on stage.”

“The Satanic Verses” was considered blasphemous by some Muslims because it fictionalized part of the life of the Prophet Muhammad. Ayatollah Khomeini issued a fatwa in 1989 ordering Muslims to kill Mr. Rushdie.

The Iranian government publicly backed the fatwa for 10 years, until at least 1998, when Iran’s president, Mohammad Khatami, said Iran no longer supported the killing. But the fatwa remains in place, reportedly with a bounty attached from an Iranian religious foundation of some $3.3 million as of 2012.

Mr. Rushdie published a memoir, “Joseph Anton,” about the fatwa. The title came from the pseudonym he used while in hiding, taken from the first names of Joseph Conrad and Anton Chekhov.

In recent years, Mr. Rushdie has enjoyed a more public life in New York City. In 2019, he spoke at a private club in Manhattan to promote his novel, “Quichotte.” Security at the event was relaxed, and Mr. Rushdie mingled with guests freely and had dinner with members of the club afterward.

In an interview last year, Mr. Rushdie was casual and easygoing as he spoke about literature from his Manhattan home, adopting the air of someone who had long ago re-entered society and reveled in being a man about town. Asked about the longstanding call for his death he answered simply, “Oh, I have to live my life.”

Jay Root reported from Chautauqua, N.Y., David Gelles from Putnam Valley, N.Y., and Elizabeth Harris from New York City. Edmund Lee and Julia Jacobs contributed reporting.