Eleven people have been killed in a stampede during the looting of a shopping mall in the South African province of Gauteng, as a wave of violent protests against the incarceration of former President Jacob Zuma grips the country, local media reported on Tuesday.

A total of 20 people had been killed in the unrest in the region, including 11 in the stampede, local media added.

Protests erupted on Friday night following the news of the ex-president’s jailing. The first waves of unrest began in Zuma’s home province of KwaZulu-Natal and have since spilled over to South Africa’s economic capital of Johannesburg in Gauteng. The protests were accompanied by looting and vandalism.

On Monday, the government dispatched the troops to quell the unrest.

Zuma, 79, turned himself in last Wednesday to begin serving a 15-month sentence he was handed for contempt of court after skipping a corruption trial.