Zuma, serving a 15-month sentence in Estcourt prison for contempt of court, was sent to a hospital outside for observation on Aug 6, days before the start of a corruption trial he has thus far avoided.

“Mr Zuma underwent a surgical procedure on Saturday, Aug 14, with other procedures scheduled for the coming days,” prison spokesman Singabakho Nxumalo said in a statement.

There was no word on a potential discharge date for Zuma, who in July asked the country’s top court to reverse his incarceration, saying it was unjust and might kill him if he catches Covid-19.

Last week, a high court postponed his corruption trial to Sept 9 after his hospitalisation. It is unclear what medical condition ails Zuma and his legal team was ordered by the judge to produce a medical report by Aug 20.

The prosecutors may appoint a doctor of their choice to assess whether Zuma is fit to stand trial.

Zuma, whose jailing last month ignited looting and unrest, faces charges with co-accused, French defence firm Thales, over a US$2 billion arms deal corruption case that led to his sacking as South Africa’s deputy president in 2005.

Zuma and Thales have denied the allegations.