JOHANNESBURG -- A South African appeals court on Thursday convicted Oscar Pistorius of murder, overturning a lower court's conviction of the double-amputee Olympian on the lesser charge of manslaughter for shooting girlfriend Reeva Steenkamp to death in 2013.

Justice Lorimer Eric Leach of the Supreme Court of Appeal delivered the ruling by the five-judge tribunal in Bloemfontein and directed the trial court, the North Gauteng High Court, to impose sentence. He did not specify when that should happen. The former track star is currently under house arrest at his uncle's mansion in Pretoria.

"The accused ought to have been found guilty of murder on the basis that he had fired the fatal shots with criminal intent," Leach said to the courtroom, in which Steenkamp's mother sat.

A date for the former athlete's new sentencing will be announced in the city of Pretoria, where he had been tried and imprisoned.