JOHANNESBURG, South Africa -- South Africa's presidency says former leader Nelson Mandela will spend Christmas Day in hospital.

The presidency says in a statement that Mandela's doctors confirmed the news on Monday. The anti-apartheid figure was admitted Dec. 8 to a hospital in Pretoria, the South African capital. He was diagnosed with a lung infection and had a procedure to remove gallstones; officials have said Mandela is improving and is responding to treatment.

South African President Jacob Zuma says the whole country is behind Mandela and he is urging people to keep the former president in their thoughts on Christmas Day and throughout the holiday season. Zuma describes Mandela, who was imprisoned under apartheid for 27 years, as an "ardent fighter."