Salman Rushdie is on a ventilator and unable to speak after being stabbed on stage in the US, his agent says.
Andrew Wylie said that the author, 75, may lose one eye after the attack at an event in New York state.
Rushdie went into hiding with police protection in the UK in 1988 after Iran’s top leader called for his murder over his novel, The Satanic Verses, which some Muslims deemed blasphemous.
Police detained a suspect named as Hadi Matar, 24, from Fairview, New Jersey.
New York State Police said the suspect ran onto the stage and attacked Mr Rushdie and an interviewer at the Chautauqua Institution in western New York state.
Rushdie was stabbed at least once in the neck and in the abdomen, authorities said. He was taken to a hospital in Erie, Pennsylvania, by helicopter.
An interviewer onstage, 73-year-old Ralph Henry Reese, suffered a facial injury but has been released from the hospital, police said.
The attack took place at the Chautauqua Institution, which hosts arts programs in a tranquil lakeside community 70 miles south of Buffalo city.
“What many of us witnessed today was a violent expression of hate that shook us to our core,” the Chautauqua Institution said in a statement.
LeVan, a Chautauqua regular, said the suspect “was trying to stab him as many times as possible before he was subdued,” adding that he believed the man “was trying to kill” Rushdie.
“There were gasps of horror and panic from the crowd,” the professor said.