Mayville: "The Satanic Verses" author Salman Rushdie was taken off a ventilator and able to talk on Saturday, a day after he was stabbed as he prepared to give a lecture in upstate New York.

Rushdie remained hospitalised with serious injuries, but fellow author Aatish Taseer tweeted in the evening that he was "off the ventilator and talking (and joking)." Rushdie's agent, Andrew Wylie, confirmed that information without offering further details.

Earlier in the day, the man accused of attacking him on Friday at the Chautauqua Institution, a nonprofit education and retreat centre, pleaded not guilty to attempted murder and assault charges in what a prosecutor called a "preplanned" crime.

An attorney for Hadi Matar entered the plea on his behalf during an arraignment in western New York. The suspect appeared in court wearing a black-and-white jumpsuit and a white face mask, with his hands cuffed in front of him.

A judge ordered him held without bail after District Attorney Jason Schmidt told her Matar, 24, took steps to purposely put himself in position to harm Rushdie, getting an advance pass to the event where the author was speaking and arriving a day early bearing a fake ID.

"This was a targeted, unprovoked, preplanned attack on Mr Rushdie," Schmidt said.

Public defender Nathaniel Barone complained that authorities had taken too long to get Matar in front of a judge while leaving him "hooked up to a bench at the state police barracks".

"He has that constitutional right of presumed innocence," Barone added.

Rushdie, 75, suffered a damaged liver and severed nerves in an arm and an eye, Wylie said on Friday evening. He was likely to lose the injured eye.

The attack was met with shock and outrage from much of the world, along with tributes and praise for the award-winning author who for more than 30 years has faced death threats for "The Satanic Verses".

Authors, activists and government officials cited Rushdie's courage and longtime advocacy of free speech despite the risks to his own safety. Writer and longtime friend Ian McEwan called Rushdie "an inspirational defender of persecuted writers and journalists across the world", and actor-author Kal Penn cited him as a role model "for an entire generation of artists, especially many of us in the South Asian diaspora toward whom he has shown incredible warmth".

US President Joe Biden said on Saturday in a statement that he and first lady Jill Biden were "shocked and saddened" by the attack.

"Salman Rushdie -- with his insight into humanity, with his unmatched sense for story, with his refusal to be intimidated or silenced -- stands for essential, universal ideals," the statement read. "Truth. Courage. Resilience. The ability to share ideas without fear. These are the building blocks of any free and open society."

Rushdie, a native of India who has since lived in Britain and the US, is known for his surreal and satirical prose style, beginning with his Booker Prize-winning 1981 novel "Midnight's Children", in which he sharply criticised India's then-prime minister, Indira Gandhi.

"The Satanic Verses" drew death threats after it was published in 1988, with many Muslims regarding as blasphemy a dream sequence based on the life of the Prophet Muhammad, among other objections. Rushdie's book had already been banned and burned in India, Pakistan and elsewhere before Iran's Grand Ayatollah Ruhollah Khomeini issued a fatwa, or edict, calling for Rushdie's death, in 1989.

Khomeini died that same year, but the fatwa remains in effect. Iran's current supreme leader, Khamenei, never issued a fatwa of his own withdrawing the edict, though Iran in recent years has not focused on the writer.

Investigators were working to determine whether the suspect, born a decade after "The Satanic Verses" was published, acted alone.

Schmidt alluded to the fatwa as a potential motive in arguing against bail.

"Even if this court were to set a million dollars bail, we stand a risk that bail could be met," Schmidt said.

"His resources do not matter to me. We understand that the agenda that was carried out yesterday is something that was adopted and it is sanctioned by larger groups and organisations well beyond the jurisdictional borders of Chautauqua County," the prosecutor said.

Barone, the public defender, said after the hearing that Matar has been communicating openly with him and that he would spend the coming weeks trying to learn about his client, including whether he has psychological or addiction issues.

Matar is from Fairview, New Jersey. Rosaria Calabrese, manager of the State of Fitness Boxing Club, a small, tightly-knit gym in nearby North Bergen, said Matar joined April 11 and participated in about 27 group sessions for beginners looking to improve their fitness before emailing her several days ago to say he wanted to cancel his membership because "he would not be coming back for a while".

Matar was born in the United States to parents who emigrated from Yaroun in southern Lebanon, the mayor of the village, Ali Tehfe, told The Associated Press.

Flags of the Iran-backed Shia militant group Hezbollah are visible across the village, along with portraits of leader Hassan Nasrallah, Khamenei, Khomeini and slain Iranian General Qassem Soleimani.

Journalists visiting Yaroun on Saturday were asked to leave. Hezbollah spokespeople did not respond to requests for comment.