South Africa’s biggest retail chains were forced to close outlets in Nigeria and Zambia on Wednesday as a wave of tit-for-tat violence against foreign-owned businesses spread across the continent.

Mobs gathered in several Nigerian cities to avenge deadly attacks on immigrant-owned premises in the townships of Johannesburg and Pretoria by looting South African supermarkets and vandalising mobile phone shops.

Vigilante gangs roaming the townships have killed at least five people in Johannesburg since the violence began last week.

The perception that Nigerians have been the chief targets of vigilante gangs in the township has prompted a diplomatic crisis between South Africa and Nigeria, Africa’s chief economic powers.

The Nigerian government announced it would boycott a World Economic Forum (WEF) conference that began in Cape Town on Wednesday after accusing South Africa of being too slow to respond to the violence.

Nigerian newspapers reported that the country was preparing to recall its high commissioner to Pretoria for consultations.