US President Barack Obama is set to meet South African President Jacob Zuma, as the country continues to hold prayers and vigils for ailing former leader Nelson Mandela.
Mr Obama’s Air Force One landed in Pretoria on Friday evening, as part of his three-country tour of Africa.
The US president has described Mr Mandela as a “hero for the world”.
The White House said he would meet members of the Mandela family, but not the former leader himself.
On Friday, Mr Obama had said it was unlikely he would see Mr Mandela, saying he did not “need a photo op” with him.
The 94-year-old is critically ill in hospital, where he was admitted on 8 June with a recurring lung infection.
His ex-wife, Winnie Madikizela-Mandela, said on Friday she felt it would not be right for President Obama to visit him while he was in a critical condition.
“I’m not a doctor but I can say that from what he was a few days ago there is great improvement, but clinically he is still unwell,” she said.
‘Legacy will linger’
Mr Obama travelled to South Africa from Senegal. During his weekend trip, the US president will visit Robben Island, where Mr Mandela was imprisoned for 18 years.
He is also expected to meet Archbishop Desmond Tutu and give a major speech at the University of Cape Town. The address is due to take place on Sunday night.
Speaking on board Air Force One after leaving Senegal, Mr Obama told reporters: “The last thing I want to do is to be in any way obtrusive at a time when the family is concerned with Nelson Mandela’s condition.”
“I think the main message we’ll want to deliver is not directly to him, but to his family – is simply profound gratitude for his leadership all these years, and that the thoughts and prayers of the American people are with him, his family and his country.”
Mr Obama met Mr Mandela in 2005 when he was still a US senator. Both men became the first black presidents of their nations and have received the Nobel Peace Prize.
The US president has described Mr Mandela as a “hero for the world”, whose “legacy will linger on through the ages”, and who had inspired his own activism as a student.
Mr Obama will finish his Africa tour in Tanzania. It is his first prolonged trip to the continent since he became president in 2009.