Salman Rushdie is off the ventilator and is talking, the president of Chautauqua Institution, where the Mumbai-born author was stabbed at an event onstage, said.

Rushdie, 75, was on a ventilator after he was stabbed by 24-year-old Hadi Matar onstage at an event on Friday at the Chautauqua Institution in western New York State. Rushdie was in surgery several hours after the attack and his agent Andrew Wylie told The New York Times (NYT) that the author was on a ventilator and could not speak.

"The news is not good. Salman will likely lose one eye, the nerves in his arm were severed, and his liver was stabbed and damaged," Wylie had said in a statement to NYT.

Matar was charged with attempted murder and assault in the stabbing of Rushdie and he pleaded not guilty. He made his appearance in court, wearing a black-and-white striped jumpsuit and handcuffed.

The New York State Police said Matar, of Fairview, New Jersey, was arrested by the Bureau of Criminal Investigation on Friday for attempted murder second degree (B Felony) and assault second degree. He was processed at State Police, Jamestown and transported to the Chautauqua County Jail. He was arraigned in centralised arraignment on Saturday and "remanded without bail" to the Chautauqua County Jail.

The attack on Rushdie drew shock and condemnation from world leaders and literary stalwarts.

US President Joe Biden said in a statement on Saturday that he and First Lady Jill Biden were "shocked and saddened" to learn of the "vicious" attack on the author.

"Salman Rushdie — with his insight into humanity, unmatched sense for the story, and refusal to be intimidated or silenced — stands for essential, universal ideals. Truth. Courage. Resilience. The ability to share ideas without fear. These are the building blocks of any free and open society. And today, we reaffirm our commitment to those deeply American values in solidarity with Rushdie and all those who stand for freedom of expression," Biden said.

"We, together with all Americans and people around the world, are praying for his health and recovery. I am grateful to the first responders and the brave individuals who jumped into action to render aid to Rushdie and subdue the attacker," he added.

UN Secretary General Antonio Guterres said he is "appalled" to learn about the attack on Rushdie. "The Secretary-General was appalled to learn of the attack on renowned novelist Salman Rushdie," a statement issued on Friday by his spokesperson said.

"In no case is violence a response to words spoken or written by others in their exercise of the freedoms of opinion and expression," Guterres said, conveying his wishes for Rushdie's early recovery.

A report in The New York Times said according to prosecutors, Rushdie was stabbed roughly 10 times in the premeditated attack.

"In court, prosecutors said that the attack on the author was premeditated and targeted," the report said, adding that Matar travelled by bus to the "intellectual retreat in western New York and purchased a pass that allowed him to attend" the talk "Rushdie was to give on Friday morning".