Mobs in South Africa have attacked shops owned by immigrants in a poor area of Johannesburg following similar violence in another part of the country that killed six people.

There was a heavy police presence in Alexandra township after rioters looted some shops, burned tyres and built street barricades overnight. Police fired rubber bullets in an attempt to stop the unrest, news outlet eNCA reported.

Several shops and cars owned by immigrants were torched in downtown Johannesburg in recent days.

Attacks on immigrants, many of them from other African countries, in and around the coastal city of Durban have subsided after the deaths of six people there, police said. Some 112 people were arrested in KwaZulu-Natal province, which includes Durban, during the riots.

Some South Africans have accused immigrants of taking jobs and opportunities away from them in a country with high unemployment. The government has said it is addressing complaints about undocumented migrants, while noting that many are living legally in South Africa.