Aerosmith's tour has been plagued by health problems
Aerosmith frontman Steven Tyler has been airlifted to hospital after falling off stage during a concert.
The 61-year-old fell while dancing to entertain the crowd, after the sound system failed at the Sturgis Motorcycle Rally in South Dakota.
Tyler was on a catwalk when he fell backward onto a couple of fans, said Mike Sanborn of the Buffalo Chip Campground, which hosted the event.
The singer was in "good spirits" as he left the grounds, Sanborn said.
"He was good natured about it," he told the Associated Press news agency. "He was talking and joking with the physician."
The singer suffered neck and shoulder injuries, Sanborn added, but it was not immediately clear how serious they were.
About 30 minutes after the accident, guitarist Joe Perry came out to tell the crowd that the remainder of the show had been cancelled.
Tyler's daughter, actress Mia Tyler, later informed fans: "Just got the news that my dad is okay. Thank you all for your wonderful prayers and positive energy!"
Journalist Matt Becker was at the concert, and said Tyler's fall looked "very rough".
"They were playing Love In An Elevator and the main sound completely blew out," he told the BBC News website.
"No-one in the crowd could hear them any more and, after about a minute, Steven Tyler came out on a catwalk and started dancing."
"It had rained about an hour earlier and they had tried to keep the stage dry, but during a spin Steven lost his balance and fell towards the audience into an area that was barricaded off - and there was no-one there to catch him.
"There is a possibility that he smacked his head off the rail that separated him from the crowd, which might have been why he was airlifted to hospital."
Becker, who runs music website Melodic Rock Concerts added there was "a little confusion in the audience" but "people were very understanding".
Aerosmith's recent concert appearances have been plagued by health problems.
Seven shows were postponed this summer after Tyler injured his leg at a gig in June, while bassist Tom Hamilton pulled out of several dates as he recovered from "non-invasive" surgery.
Guitarist Brad Whitford also missed some concerts after hurting his head, and the band cancelled a gig in Venezuela in January when guitarist Joe Perry developed "unforeseen complications" with his replacement knee.