South African President Jacob Zuma's office says former president and antiapartheid icon Nelson Mandela is "responding positively" to treatment for a recurring lung infection.
Mandela, who is 94, was admitted to hospital overnight.
The statement from Zuma's office said Mandela "remains under treatment and observation in hospital," without giving any further details.
Mandela was hospitalized for nearly three weeks in December 2012 for treatment of a lung infection and surgery to remove gallstones.
Mandela was released from prison in 1990 after serving 27 years and became South Africa's first black president in the country's first all-race elections in 1994.
He is revered around the world for preaching reconciliation between South Africa's majority blacks and the minority whites who formerly ruled the country.
Based on reporting by Reuters, AFP, and AP