a shop owner from mozambique has died from his injuries in a johannesburg hospital amid xenophobic violence .
at least six have been killed by armed gangs wielding machetes , hammers and sticks who are targeting foreigners .
the anti-immigration violence in south africa has forced thousands of people to flee their homes and the country .
president jacob zuma has called for an end to ` shocking and unacceptable ' attacks on africans and south asians .