South Africans have said their thoughts are with former president Nelson Mandela, who remains in a "serious but stable" condition after being taken to hospital to be treated for a recurring lung infection.
Mr Mandela, 94, has been treated in hospital several times in recent months, with the last discharge coming on April 6 after doctors diagnosed him with pneumonia and drained fluid from his lung area.
He has been particularly vulnerable to respiratory problems since contracting tuberculosis during his 27-year imprisonment under apartheid.
A small girl and her father stood outside Mr Mandela's Johannesburg home with a stone on which was written a get well message for Mr Mandela, who helped end white racist rule and became the country's first black president in all-race elections in 1994. A young boy brought a bouquet of flowers that he handed over to guards at the house.
Elsewhere in the city, some worshippers prayed for Mr Mandela during an outdoor gathering.
"If the time comes, we wish for him a good way to go," said Noel Ngwenya, a security officer who was in the congregation.
A statement from the office of current president Jacob Zuma said: "During the past few days, former president Nelson Mandela has had a recurrence of lung infection. This morning (Saturday) at about 1:30am, his condition deteriorated and he was transferred to a Pretoria hospital."
It said Mr Mandela is receiving expert medical care and "doctors are doing everything possible to make him better and comfortable".
Mr Zuma wished Mr Mandela a quick recovery on behalf of the government and the nation and requested that the media and the public respect the privacy of the former leader and his family, the statement said.
Mr Mandela's wife, humanitarian activist Graca Machel, cancelled an appearance at an international forum on hunger and nutrition in London, citing "personal reasons," said Colleen Harris, a spokeswoman for the meeting.