(AFP) - A South African court Wednesday ordered former president Jacob Zuma to return to prison, invalidating the medical parole he was granted in September.

The decision to place Zuma on medical parole is "declared unlawful and set aside", read the ruling by High Court Judge Elias Matojane.

Within hours, Zuma's lawyers had filed a motion to appeal. The move means that Zuma will not return to prison until the appeal is heard.

In their filing, his lawyers said the court's decision "amounts to cruel and degrading punishment with no due regard to the patient's healthcare, dignity and other human rights."

Zuma, 79, was jailed in July for 15 months for contempt of court, after he refused to give testimony to corruption investigators.

His jailing sparked violent protests and looting in his home province of KwaZulu-Natal that spread to the financial hub Johannesburg in July, claiming over 350 lives.

That was the deadliest violence in South Africa since the end of white-minority rule in 1994.

Current President Cyril Ramaphosa has described the unrest as an orchestrated attempt to destabilise the country.

Zuma was granted medical parole on September 5, but the exact reasons were never revealed. While in prison, he was taken to hospital for surgery to treat an undisclosed ailment.

In addition to the investigation by a special anti-corruption panel, Zuma is also enmeshed in a drawn-out corruption trial relating to a 1999 purchase of arms from five European firms.

Deputy president at the time, Zuma is accused of pocketing bribes from French defence giant Thales and faces 16 charges of fraud, graft and racketeering.

© Agence France-Presse