South African sports star Oscar Pistorius has vowed to fight allegations he murdered his girlfriend and has branded her death a "terrible tragedy".

The 26-year-old Paralympian, nicknamed Blade Runner, hit headlines across the world on Thursday (14Feb13) when he was arrested in connection with the death of his model partner Reeva Steenkamp, who was shot four times at his home in Pretoria, South Africa in the early hours.

He has since been charged with murder and prosecutors have confirmed they will argue the killing was premeditated.

Pistorius' relatives have now released a statement on the incarcerated star's behalf, revealing the athlete is determined to contest the murder charge.

The statement reads, "The alleged murder is disputed in the strongest terms... He (Pistorius) has made it very clear that he would like to send his deepest sympathies to the family of Reeva. He would also like to express his thanks through us today for all the messages of support he has received - but as stated our thoughts and prayers today should be for Reeva and her family - regardless of the circumstances of this terrible, terrible tragedy."

Local reports previously suggested Pistorius had mistaken his girlfriend for a burglar when she entered his home for a Valentine's Day (14Feb13) surprise, but police officials dismissed the story, insisting the reports had not come from an official source. Steenkamp, 30, was reportedly shot four times in the head and chest.