At least 30 people have died in the violence which has been engulfing parts of South Africa since the country’s former President Jacob Zuma handed himself into police last week.
Almost 800 people have been arrested in the unrest which began as protests following Zuma’s jailing on Thursday.
But protests turned violent over the weekend, with fires set, highways blocked and businesses looted.
The military has now been deployed to help the overstretched police.
Police Minister Bheki Cele told journalists on Tuesday that if the looting continued, there was a risk areas could run out of basic goods.
However, Defence Minister Nosiviwe Mapisa-Nqakula said there was not yet a need to declare a state of emergency over the violence in KwaZulu-Natal and Gauteng provinces.
KwaZulu-Natal Premier Sihle Zikalala said some 26 people had been killed in the province so far, including a 15-year-old boy, EWN reports. Six deaths have been confirmed in Gauteng, news agency AFP says.
Officials have accused some groups are taking advantage of the anger over Zuma’s imprisonment to commit criminal acts, while others have said anger over unemployment and poverty are fuelling the chaos.