Nelson Mandela has spent a night in hospital after he was admitted for tests, South Africa's presidency says.
Spokesman Mac Maharaj said there were no updates on the 94-year-old's condition since he went to a hospital in Pretoria on Saturday afternoon.
In an earlier statement, Mr Maharaj said the medical tests for the anti-apartheid leader and former president were scheduled and that doctors have indicated there is no cause for "alarm".
Mr Mandela was in hospital for nearly three weeks in December before going home on December 26.
At that time, he was treated for a lung infection and had a surgical procedure to remove gallstones.