A court in South Africa has ruled that Oscar Pistorius was guilty of murder, not manslaughter, in the killing of his girlfriend Reeva Steenkamp.

He was previously convicted of culpable homicide for shooting her through the closed door of a lavatory at their home on February 14, 2013, and is currently under house arrest after serving a year in prison. He has said that reading his Bible and prayer has helped him deal with what happened.  

The defence had argued that Pistorius had shot her by mistake, thinking she was a burglar. But now a judge has ruled the verdict was flawed and convicted him of murder.

Judge Lorimer Leach of the Supreme Court of Appeal delivered the ruling by the five-judge appeals court in Bloemfontein and said the trial court, the North Gauteng High Court, should impose a new sentence.

He said that regardless of who might have been behind the door, Pistorius ought to have known someone could be killed if he fired.

"The identity of his victim is irrelevant to his guilt," the judge said, adding that Pistorius did "not take that most elementary precaution of firing a warning shot".

The ruling will see Pistorius return to prison, where he will face a term of up to 15 years, the minimum for murder. He was originally sentenced to five years, of which he served a year, with the remainder due to be served under house arrest.

Reeva Steenkamp's mother June, was present at the hearing and was seen afterwards outside the court being embraced by members of the African National Congress Women's League, who were singing songs of celebration.