South Africa's president has said Barack Obama will still meet Nelson Mandela, despite the national hero's failing health.
The US President is due to meet his fellow Nobel peace laureate during a short tour of Africa, but the 94-year-old is critical in hospital with a lung infection.
Mr Zuma said: "Madiba (Mandela's clan name) has been unwell for quite a while. There's nothing that's going to stop the visit because Mandela is sick. If you stopped that visit, people would ask questions. Obama is coming whilst Madiba is in hospital not well."
Jack Hillmeyer, a spokesman for the US Embassy in Pretoria, told the Daily Telegraph: "Obviously the president and the first lady and everyone is keeping him their thoughts and prayers. We certainly will be watching and following developments but for now, we are continuing with preparations (for the visit)."
On Friday, before Mr Mandela's health took a downturn, Ben Rhodes, a deputy US national security adviser, said of the visit: "Ultimately, we want whatever is in the best interests of his (Mandela's) health and the peace of mind of the Mandela family. We will be in touch with them. If he has an opportunity to see the family in some capacity, that's certainly something that we may do."
Before visiting South Africa, President Obama is due to visit Senegal. His final stop on the tour will be in Tanzania.
Mandela's deterioration this weekend, two weeks after being admitted in a serious but stable condition, has caused a perceptible switch in mood from prayers for recovery to preparations for a fond farewell.
Since stepping down in as president in 1999 after one term, Mandela has stayed out of active politics in a country with the continent's biggest and most important economy.
His last public appearance was waving to fans from the back of a golf cart before the final of the soccer World Cup in Johannesburg's Soccer City stadium in July 2010.
During his retirement, he has divided his time between his home in the wealthy Johannesburg suburb of Houghton, and Qunu, the village in the poor Eastern Cape province where he was born.
The public's last glimpse of him was a brief clip aired by state television in April during a visit to his home by Zuma and other senior ANC officials.