The South African prosecutors' office says it will appeal against Oscar Pistorius' six-year prison sentence for the murder of girlfriend Reeva Steenkamp, calling it "shockingly" lenient.

South African Olympic runner Oscar Pistorius has been sentenced to six years in prison for the murder of his girlfriend, Reeva Steenkamp, on Valentine's Day 2013.

Oscar Pistorius is a "broken man" after killing girlfriend Reeva Steenkamp because he lost the woman he said he loved, a psychologist called by his lawyers testified Monday.