Author Salman Rushdie, who suffered years of Islamist death threats after writing The Satanic Verses, has been attacked on stage in New York state.
The Booker Prize winner, 75, was speaking at an event at the Chautauqua Institution at the time.
New York State Police said a male suspect ran up onto the stage and attacked Mr Rushdie and an interviewer.
“Rushdie suffered an apparent stab wound to the neck,” the police statement said.
The author was transported by helicopter to a local hospital. His condition is not currently known.
The interviewer, Henry Reese, also suffered a minor head injury. Mr Reese is the co-founder of a non-profit that provides sanctuary to writers exiled under threat of persecution.
The suspect was immediately taken into custody, police said.
A video posted online shows attendees rushing onto the stage immediately following the incident.
The Indian-born novelist catapulted to fame with Midnight’s Children in 1981, which went on to sell over one million copies in the UK alone.
But Mr Rushdie’s fourth book, in 1988 – The Satanic Verses – forced him into hiding for nine years.
The surrealist, post-modern novel sparked outrage among some Muslims, who considered its content to be blasphemous, and was banned in some countries.
A year after the book’s publication, Iran’s Supreme Leader Ayatollah Khomeini called for Mr Rushdie’s execution and offered a $3m (£2.5m) reward.
Dozens of people died in the violence that followed its publication, including murdered translators of the work.
The bounty over Mr Rushdie’s head remains active, although Iran’s government has distanced itself from Khomeini’s decree.
The author, who has British and American citizenship, is a vocal advocate for freedom of expression and has defended his work on several occasions.
When he was knighted in 2007 by Queen Elizabeth II, it sparked protests in Iran and Pakistan, where one cabinet minister said the honour “justifies suicide attacks”.
Literary events attended by Mr Rushdie have been subject to threats and boycotts in the past.
His appearance at the Chautauqua Institution event, in western New York, was the first in a summertime lecture series hosted by the non-profit organisation.
A spokesman for the organisation’s on-site police department declined to comment when contacted by the BBC.
An artist at the venue said that rehearsals had been going as normal this morning until the attack inside its amphitheatre.
The venue has been on lockdown since, she said.
PEN America, a prominent US free speech group for authors, said it was “reeling from shock and horror” at news of the attack. Mr Rushdie was the organisation’s president from 2004 to 2006.
“We can think of no comparable incident of a public violent attack on a literary writer on American soil,” its statement reads.
New York Governor Kathy Hochul vowed to “assist however needed in the investigation” into the stabbing.
“Our thoughts are with Salman and his loved ones following this horrific event,” she wrote.