South African state prosecutors have appealed the conviction and sentence given to track star Oscar Pistorius.
Pistorius was found guilty of culpable homicide for shooting his girlfriend Reeva Steenkamp last year, and last month began serving a five-year prison sentence.
But South Africa's National Prosecuting Authority had said it was "disappointed" with both decisions.
The NPA said Tuesday that it has filed an appeal in the North Gauteng High Court. It said it could not discuss the matter publicly until judgement is delivered by the court.
Pistorius originally faced more serious charges of murder, but Judge Thokozile Maspia ruled that prosecutors did not prove that he shot Steenkamp intentionally.
Critics including the Women's League of South Africa's ruling ANC party have said the conviction and sentence are too light.
Pistorius killed his girlfriend the night of February 14, 2013, when he fired four bullets through a locked bathroom door at his house in Pretoria. During his trial, Pistorius said he believed he was shooting at a nighttime intruder.
The athlete's lawyers have said they expect Pistorius will serve about 10 months of his sentence in prison before completing his time under house arrest.
Pistorius is known as the "blade runner" for his carbon-fiber prosthetic legs. He became the first double-amputee to compete in the Olympics when he ran for South Africa at the 2012 games in London.