The South African government says former president Nelson Mandela is spending Christmas in hospital.
Mr Mandela, 94, was admitted to hospital two weeks ago and has been treated for a lung infection and gallstones.
The BBC reports there is growing concern in South Africa about his health.
Mr Mandela was imprisoned for 27 years for leading the struggle against white-minority rule.
The government says he is being treated for a recurring lung infection at a hospital in the capital, Pretoria. He also had an operation to remove gallstones.
Mr Mandela contracted tuberculosis in the 1980s while detained on Robben Island prison.
He has been admitted to hospital on three occasions in the past two years.
In January 2011, he was treated for a serious chest infection in Johannesburg.
In February this year, he was again admitted to a Johannesburg hospital because of abdominal pains. He was released the following day after tests revealed nothing serious.
Mr Mandela served as South Africa's first black president from 1994 - 1999. He retired from public life in 2004 and is rarely seen in public.
President Jacob Zuma has urged South Africans to pray for him.
Mr Mandela lives in Qunu, a rural village in Eastern Cape province, where he spent his childhood.
He was last seen in public in 2010, during the closing ceremony of the FIFA World Cup.
In May, footage of Madiba seated on a couch, was shown on television when he was visited by ANC leaders to present him with a symbolic flame to mark the party's 100 years.