Nelson Mandela, the former South African president and anti-apartheid leader, has been admitted to a hospital for a scheduled medical check-up and doctors say there is no cause for alarm, the president's office said.
Presidential spokesman Mac Maharaj said 94-year-old Mr Mandela went for tests "to manage existing conditions in line with his age" at a hospital in Pretoria, the capital.
"Doctors are conducting tests and have thus far indicated that there is no reason for any alarm," Mr Maharaj said in a statement. He appealed for the public to respect the privacy of Mr Mandela and his family.
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.
The former president has become increasingly frail over the years. In January 2011, Mr Mandela was admitted to a Johannesburg hospital for what officials initially described as tests but what turned out to be an acute respiratory infection. He was discharged days later. He also had surgery for an enlarged prostate gland in 1985.