Nelson Mandela Foundation said on Thursday violence can be a rational response to racism and for some communities is the only way to elicit change, as protests raged across the United States over the death of George Floyd.

Floyd died after a police officer knelt on his neck for nearly nine minutes, video footage showed that and went viral on various social media platforms, sparking outrage across the United States and beyond.

The South Africa's foundation, set up to guard the legacy of Nelson Mandela, the country's first democratically-elected president, said that violence is often too readily dismissed as the work of extremists or criminals, when it can be the result of careful calculation by communities who "see that only such action elicits the desired response from the state".

"When communities are confronted by both resilient structural violence and attacks on their bodies, violent responses will occur.The use of violence can be rational and carefully targeted," its statement continued.

Violent struggle helped bring an end to a system of segregation and white minority rule in South Africa. But 26 years after the end of apartheid, the country is still grappling with racial tensions and massive inequality, with the foundation saying democracy had not "yet ensured black lives matter as much as white lives".

(With input from agencies)