Former President Nelson Mandela of South Africa is in hospital in Pretoria.
The office of President Jacob Zuma said he is doing well and there is no cause for alarm.
Mr Mandela, 94, spent more than two decades in prison under the former white apartheid regime.
He served as South Africa's first black president between 1994 - 1999, and received the Nobel Peace Prize in 1993.
Mr Mandela has rarely appeared in public since 2004, when he retired from public life.
In January 2011 he was treated for a serious chest infection, and a year later underwent a diagnostic procedure for an abdominal problem.
Officials said on Saturday that he would need medical attention "from time to time" because of his age.
The statement gave no further details of Mr Mandela's health.
The BBC reports Mr Mandela spends almost all his time in Qunu, a rural village close to where he was born. He is known to be frail and his memory is fading.