South African police  have arrested dozens of people in Johannesburg on September 2 after rioters looted shops, burned tyres and blocked road junctions – the second outbreak of urban rioting in a week. (Image: Johannesburg).

Police had no answer what exactly had triggered the violence, however it is generally considered that the social context has deteriorated: unemployment at close to 30%, widespread poverty and income disparities have all been blamed for recent outbreaks and attacks on immigrants.

Last week, hundreds of protesters in the administrative capital Pretoria set fire to buildings, looted mostly foreign-owned businesses and clashed with police, who started to fire rubber bullets at the crowds in attempt to stop further devastation.

Taxi drivers issued an alert to commuters asking them to avoid Pretoria downtown.

However, Nigerian Foreign Minister Geoffrey Onyeama said Nigerian shops had been targeted by “mindless criminals” and promised to take “definitive measures“.