An estimated 13,000 people flee homes after violence against foreigners . Attacks have been reported in Johannesburg 's poorest areas . Police arrest more than 200 people after at least 20 are killed . Evidence of the violence was seen in smoke rising from burned homes in one Johannesburg neighborhood . Zimbabweans who have fled their own country are driven from refugee camps .
An estimated 13,000 people flee homes after violence against foreigners . Attacks have been reported in Johannesburg 's poorest areas . Police arrest more than 200 people after at least 20 are killed . Zimbabweans who have fled their own country are driven from refugee camps .