A South African judge has declared that prosecutors can move forward with an appeal against the acquittal of murder charges for Oscar Pistorius, who was convicted of the lesser charge of culpable murder for killing his girlfriend in 2013.

Earlier this year, the Paralympic athlete, also known as the "Blade Runner," was found not guilty of murder in the shooting death of Reeva Steenkamp on Feb. 14, 2013, whom he claims he killed by mistake because he thought she was a home intruder.

Judge Thokozile Masipa, however, found him guilty of culpable homicide, which is comparable to manslaughter. She then sentenced the double-amputee runner to five years at Pretoria's Central Prison, but he is only required to serve 10 months behind bars before he can be moved to community supervision or house arrest.

Prosecutors criticized the judge's verdict as being too lenient and argued that the sentence was "shockingly light."

Although Judge Masipa said prosecutors could appeal against the acquittal, she did not permit an appeal against the five-year sentence.

The case will now be heard by the South Africa's Supreme Court of Appeal, BBC reports. If Pistorius is found guilty of murder, he would face a minimum of 15 years in prison.

Pistorius' lawyers, on the other hand, opposed the appeal request and said the sentence was not light.

"It's incorrect to say it's a light sentence. It's not," said defense lawyer Barry Roux, reports BBC News.

Addressing the judge, he added that the state can only appeal on matters of law, and not of fact.

"Their problem is they don't like your factual finding. They don't appreciate that. You absolutely, correctly applied the law," he said,

If the court does not grant prosecutors an appeal, then they will be free to petition the Supreme Court of Appeals to hear their case.