Former South Africa President Nelson Mandela is in a stable condition after undergoing surgery.
Officials said he was taken to hospital overnight for a "long-standing abdominal complaint" which needed "proper specialist medical attention".
A government spokesman said the former leader was "in good spirits and well".
The 93-year-old statesman and anti-apartheid icon has suffered declining health in recent years.
In a statement, President Jacob Zuma's office said the "love and good wishes of all South Africans and people throughout the world" were with Mr Mandela, and asked for his family to be given privacy.
The statement did not say which hospital he had been admitted to but there are suggestions it was a military hospital in the capital, Pretoria.
Mr Mandela had returned to Johannesburg last month from his rural home in the Eastern Cape and in January last year, he received treatment in the city's Milpark hospital for a serious chest infection.
"I can assure you that the former president is in good spirits and well," said Mac Maharaj, a spokesman for Mr Zuma