Nelson Mandela is making "steady progress" while being treated for a recurring lung infection and he had a full breakfast on Friday, South African authorities said.

The office of President Jacob Zuma released a statement in which it said the former president and anti-apartheid leader was in good spirits after being taken late Wednesday to a hospital in the capital, Pretoria.

"The doctors report that he is making steady progress. He remains under treatment and observation in hospital," the statement said.

"We would like to repeat our appeal for the media and the public to respect the privacy of Madiba and his family," it said, using Mandela's clan name, a term of affection.

It is 94-year-old Mandela's third trip to a hospital since December. At that time, he spent three weeks in a hospital in Pretoria, where he was treated for a lung infection and had a procedure to remove gallstones. Earlier this month, he was hospitalized overnight for what authorities said was a successful, scheduled medical test.

The Nobel Peace Prize laureate has been particularly vulnerable to respiratory problems since contracting tuberculosis during his 27-year imprisonment for fighting white racist rule in his country.

President Barack Obama said Thursday he was concerned about Mandela's health, but noted he was as strong physically as he has been in leadership and character. Obama said he was sending his thoughts and prayers to Mandela, and he described him as a hero and an inspiration who gave everything to his people.

Zuma's office said Thursday that doctors were acting with extreme caution because of the advanced age of Mandela, who has become increasingly frail in recent years.

Mandela, who became South Africa's first black president in 1994, is a revered figure in his homeland, which has named buildings and other places after him and uses his image on national bank notes.