- Oscar Pistorius has been injured during a fight in prison in South Africa
- He reportedly started fight with 'inmate he knows well' queuing for phone
- Last month, Pistorius, 31, had his murder sentence increased to 13 years
- He shot and killed girlfriend Reeva Steenkamp, 29, on Valentines Day 2013
Oscar Pistorius has been injured in a prison brawl after allegedly starting a fight with another inmate while waiting to use a pay phone.
The paralympian, who had his murder sentence more than doubled last month, was queuing to use the phone at Atteridgeville Correctional Centre, near Pretoria, when he reportedly began fighting with an inmate 'he knows well'.
Pistorius reportedly 'sustained a bruise' in the altercation on December 6, but the fight could see him lose privileges such as access to the jail tuck shop and the phone that started the fight,
Pistorius, 31, is still classified as 'low risk', but may be re-classified if an investigation finds that he was the one that started the fight.
The other man the paralympian tussled with is also detained on the special care unit 'where inmates with special needs and different sexual orientation are held for their own protection', spokesman Singabakho Nxumalo told MailOnline.
Pistorius had his sentence for the 2013 murder of his girlfriend Reeva Steenkamp, 29, increased to 13 years last month in a successful appeal by prosecutors.
The Supreme Court ruling was widely welcomed in his native South Africa, including by the family of his victim.
'He was involved in an altercation with another inmate over the use of a public phone in the special care unit, where both offenders are detained, the men know each other well,' Mr Nxumalo from the Department of Correctional Services said.
'As standard operating procedure regarding cases of alleged assaults, the Department of Correctional Services has launched an internal investigation into the matter to establish the facts and to ensure that appropriate action is taken as incidents of assault are not allowed. We want to know that proper security protocols were followed by prison staff.
'If Oscar Pistorius is found to be at fault, he could lose his privileges and be re-classified if he is no longer considered 'low risk'.'
Pistorius is being held at the 'relaxed' Atteridgeville Correctional Centre, near his wealthy family's sprawling compound in the capital Pretoria, but could face a return to the notorious maximum security facility Kgosi Mampuru II where he served his first year behind bars.
Atteridgeville only houses inmates who are serving a maximum of six years, and has upgraded facilities, including ensuite bathrooms for prisoners with special needs.
Today, his brother Carl posted an encouraging Winnie the Pooh-quote on Twitter after news of the brawl emerged, writing, 'Always remember: You're braver than you believe, stronger than you seem, and smarter than you think'.
Pistorius shot and killed 29-year-old Ms Steenkamp on Valentine's Day in 2013 when he fired four times through the door of his bedroom toilet, claiming he had mistaken her for an intruder.
Last month, Supreme Court of Appeal judges were 'unanimous' in sentencing Pistorius to South Africa's minimum 15 years for murder, ruling Pistorius' six year punishment sentence for killing Reeva Steenkamp had been 'inappropriate'.
The time he has already served behind bars will be deducted from that punishment, so the effective sentence is 13 years.
At the time, Pistorius's father Henke told MailOnline, he was 'shocked' and 'disillusioned' by the judgement, calling South Africa increasingly 'unpredictable and dangerous'.
'I am unbelievably surprised, disillusioned and very disappointed. There are many influences and role players in the execution of our South African law, which makes the country progressively more unpredictable and dangerous,' he said in a phone call.
The finding was the second time the appeal judges have overruled Judge Thokozile Masipa, who presided over Pistorius' murder trial and originally cleared the disgraced sprinter of murder.
Changing times: Pistorius runs in the men's 400-meter semifinal during the 2012 Summer Olympics in London +5
Changing times: Pistorius runs in the men's 400-meter semifinal during the 2012 Summer Olympics in London
In a damning written ruling, the appeal court was scathing of Pistorius, finding that he had failed to be frank at his trial, and subsequent appeal, or show genuine remorse for taking his lover's life.
Unusually, the court also singled out Judge Masipa for criticism, slamming her six year sentence for 'trivialising' the seriousness of Pistorius' crime.
'I find it difficult on the evidence to accept that the respondent is genuinely remorseful', Judge Seriti concluded, adding, 'the respondent has failed to explain why he fired the fatal shots, .. to my mind, the attempt by the respondent to apologise to the deceased's family does not demonstrate any genuine remorse on his part.
'He failed to take the court fully into his confidence despite having an opportunity to do so during the second sentencing proceedings. It is clear herefrom that the respondent is unable to appreciate the crime he has committed. '
The senior judge found there 'are no substantial or compelling circumstances which can justify the departure from the prescribed minimum sentence.'
He damned Judge Masipa's decision to hand down six years to the athlete as 'shockingly lenient to the point where it has the effect of trivializing this serious offence.'
Pistorius pleaded not guilty at his trial in 2014 and has always denied that he killed Steenkamp in a rage, saying he mistook her for a burglar.
Previously a role model for disabled people worldwide, Pistorius was released from jail in 2015 after serving one year of a five-year term for culpable homicide - the equivalent of manslaughter.
However, shortly after his release that year, Pistorius found was guilty of murder, irrespective of whoever was behind the door when he opened fire with a pistol he kept under his bed.
He returned behind bars after his conviction, and is being held at a prison in Pretoria.
The year before he killed Steenkamp, Pistorius became the first double-amputee to race at the Olympics when he competed at the London 2012 games.