The South African government has confirmed reports the ambulance transporting Nelson Mandela to hospital two weeks ago broke down on the way and the former president had to wait 40 minutes until a replacement arrived.
A spokesperson for the president says doctors are satisfied Mr Mandela suffered no harm during the wait.
"All care was taken to ensure that the former president's medical condition was not compromised by the unforeseen incident," presidential spokesman Mac Maharaj said.
Mr Mandela was taken to hospital in the early hours of 8 June. It is the fourth hospital stay since December for the former president has a history of lung problems dating back to his time at the Robben Island prison camp near Cape Town.
The government has made no comment on reports by the American network CBS that Mr Mandela, who has been in hospital for two weeks, is in an unresponsive state and has not opened his eyes for days. It is saying only that he remains in a serious but stable condition.