Shops were looted overnight and a section of the M2 highway was closed in Johannesburg on Sunday, as sporadic acts of violence following the jailing of former South African President Jacob Zuma spread to the country's main economic hub.
The unrest had mainly been concentrated in Zuma's home province of KwaZulu-Natal (KZN), where he started serving a 15-month sentence for contempt of court on Wednesday night.
Zuma's sentencing and subsequent imprisonment have been seen as a test of the post-apartheid nation's ability to enforce the law fairly -- even against powerful politicians -- 27 years after the African National Congress (ANC) ousted the white minority rulers to usher in democracy.
But his incarceration has angered Zuma's supporters and exposed rifts within the ANC.
Police said criminals were taking advantage of the anger to steal and cause damage. National intelligence body NatJOINTS warned that those inciting violence could face criminal charges.
NatJOINTS said in a statement that 62 people had been arrested in KZN and Gauteng, the province where Johannesburg is located, since the violence began.
The Johannesburg Metropolitan Police Department (JMPD) said there had been looting in the Alexandra township and Jeppestown suburb on Saturday night. The M2 was closed off after there were reports of shots being fired at passing vehicles.
Protests were ongoing in the Hillbrow neighbourhood on Sunday morning, JMPD spokesman Wayne Minnaar said.
KZN police spokesman Jay Naicker said there had also been more looting in eThekwini, the municipality that includes Durban. "We saw a lot of criminals or opportunistic individuals trying to enrich themselves during this period," he said.
Zuma was given the jail term for defying an order from the constitutional court to give evidence at an inquiry that is investigating high-level corruption during his nine years in power until 2018.
He denies there was widespread corruption under his leadership but has refused to cooperate with the inquiry, which was was set up in his final weeks in office.
Zuma has challenged his sentence in the constitutional court, partly on the grounds of his alleged frail health and the risk of catching Covd-19. That challenge will be heard on Monday.
Parliament's presiding officers said on Sunday that they were "sympathetic to the personal difficulties confronting former President Jacob Zuma. However, the rule of law and supremacy of the constitution must prevail".