South African prosecutors say they will take court action in order to secure a longer prison sentence for Olympic athlete Oscar Pistorius.

He was jailed for six years earlier this month for murdering his girlfriend Reeva Steenkamp in 2013.

Prosecutors argue that Pistorius' sentence is inappropriate for the crime of murder and "shockingly too lenient".

They also argue that the sentence is unjust and could bring the justice system into disrepute.

Pistorius was initially given a five-year term for manslaughter, but was found guilty of murder on appeal last December.

He admitted shooting her, but said he had mistaken Ms Steenkamp for an intruder and acted out of fear.

Rise and fall of Oscar Pistorius

• August 2012: Competes in London Olympics and Paralympics, where he won a gold medal

• February 2013: Shoots dead his girlfriend Reeva Steenkamp

• March 2014: Trial begins

• September 2014: Judge finds Pistorius guilty of culpable homicide

• October 2014: Begins five-year sentence

• October 2015: Transferred to house arrest

• December 2015: Appeal court changes verdict to murder

• July 2016: Sentenced to six years in jail for murder