Disgraced American football star O.J. Simpson, whose racially charged 1995 murder trial riveted the nation, was released from jail on parole early Sunday after nine years behind bars for armed robbery.

Simpson, 70, left the Lovelock Correctional Center in the western state of Nevada just after midnight, prison spokesperson Brooke Keast said. "I don't know where he was headed," Keast told AFP.

Simpson was granted parole at a hearing in July and his earliest release date was set for October 1, but he had widely been expected to be freed no earlier than Monday.

"To ensure public safety and avoid possible incident," Keast said, commenting on Simpson's early release at eight minutes past midnight local time (0708 GMT Sunday).

Simpson plans to relocate to Florida following his release from the medium-security prison where he has been serving his sentence, his lawyer, Malcolm LaVergne said earlier.

Simpson was famously found not guilty in 1995 of the grisly murders of his ex-wife, Nicole Brown Simpson, and a male friend, Ron Goldman, in a case that transfixed the country and became known as the "Trial of the Century."

But the former National Football League running back and actor was sent to prison in 2008 for his role in an armed robbery the previous year of two sports memorabilia dealers at a Las Vegas resort.

Simpson claimed at his trial that he was just seeking to recover personal items from the dealers, and he repeated that explanation at his parole board hearing in July, where the four-member panel voted unanimously for his release.