Nelson Mandela leaves the chapel after attending the funeral of his great-granddaughter Zenani Mandela in Johannesburg, South Africa. South African President Jacob Zuma says that former President Nelson Mandela has been admitted to hospital in Pretoria to undergo tests. Zuma issued a statement Saturday, Dec. 8, 2012 saying that Mandela is "doing well and there is no cause for alarm." (AP Photo/Siphiwe Sibeko, Pool, File)

JOHANNESBURG (AP) — Anti-apartheid icon Nelson Mandela is spending a twelfth day in a South African hospital after being diagnosed with a lung infection and undergoing gallstone surgery.

South Africa’s government has said the 94-year-old Mandela was admitted Dec. 8 to a hospital in the country’s capital, Pretoria. Officials said Mandela underwent an endoscopic surgery to remove gallstones Saturday after doctors treated him for a recurrent lung infection.

On Tuesday, President Jacob Zuma said in a statement that Mandela required “extraordinary care” due to his age and could spend several more days in the hospital recovering.

Mandela is revered for being a leader of the struggle against racist white rule in South Africa, serving 27 years in prison for his beliefs. He served one five-year term as president before retiring from public life.

Copyright 2012 The Associated Press.