"This is an extraordinary, unthinkable tragedy that has claimed a remarkable leader of a nation with whom South Africa enjoys strong bilateral relations," Ramaphosa said.
Ramaphosa visited Iran as deputy president in 2015 and in 2023 welcomed Raisi to a summit of the BRICS group in Johannesburg, where the Islamic republic was formally invited to join.
Iran became a full member of the intergovernmental forum in January, along with Brazil, Russia, India, China, South Africa, Egypt, Ethiopia and the United Arab Emirates.