The US National Security Adviser said Saturday that the attack on author Salman Rushdie is "appalling".

"We’re all praying for his speedy recovery," Jake Sullivan wrote on Twitter. "And we’re thankful to good citizens and first responders for helping him so swiftly.”

Rushdie's agent told the New York Times that the award-winning author, who was attacked Friday on stage in the state of New York, is on a ventilator and cannot speak, his arm and liver are injured and he might lose an eye.

The suspect who attacked Rushdie was taken into custody, police said Friday.

Pictures on social media showed Rushdie, whose works have prompted death threats, lying on stage at the Chautauqua Institution as police and bystanders attempted to provide first aid.

Footage also showed bystanders rushing to the stage in the immediate wake of the attack.

The attack took place before a lecture he was about to present.

Rushdie suffered a stab wound to his neck and was transported to a hospital, New York State Police said in a statement.

An interviewer also suffered a minor head injury, police added.

Rushdie is the author of several novels that won widespread acclaim, including Midnight's Children, which won the Booker Prize in 1981.

But his book, “The Satanic Verses," was the subject of controversy seven years later, with late Iranian Ayatollah Ruhollah Khomeini issuing a fatwah calling for his death because of the novel.

Ayatollah Ali Khamenei, Khomeini's successor, had a tweet deleted in 2019 that said the fatwah remained in place.