A white woman who worked as a personal assistant to Nelson Mandela has stirred unease about race relations in South Africa after criticizing the current president for allegedly anti-white remarks.

Zelda la Grange has since apologized for her Twitter comments, which triggered accusations that she was herself a racist steeped in the ideology of white minority rule. Apartheid ended when Mandela, who died in 2013 at the age of 95, became South Africa's first black president in 1994.

La Grange had accused President Jacob Zuma of making business conditions difficult for white investors and making it clear that whites "are not wanted or needed in South Africa."

After Mandela died, la Grange said in a tribute that the anti-apartheid leader's legacy had inspired unity among South Africans.