One of the robbery suspects fired a shot and both assailants fled when a family driver returned fire. No one was injured and no property was stolen in the incident that took place at a family home in Johannesburg, said police Brigadier Govindsamy Mariemuthoo.
“The driver transporting the grandchildren of Mr Mandela had just moved into the gates when they were approached by two unknown gunmen,” he said.
The group was ordered to lie on the ground and then there was the exchange of gunfire.
The attempted robbery came about a month after Mandela attended the funeral of his granddaughter Zenani Mandela, 13, who was killed in a car crash.
Mandela was with his family on Sunday for birthday celebrations when he turned 92.