Members of the White House travelling staff walk to a group of helicopters about to transport US President Barack Obama from a soccer field in Johannesburg, June 29, 2013. Obama flew to Pretoria on Saturday to meet with South Africa's President Jacob Zuma at the Union Buildings. [Photo/Agencies]

A child stands near messages of support for ailing former South African President Nelson Mandela and an image of US President Barack Obama outside the Medi-Clinic Heart Hospital, where Mandela is being treated, in Pretoria June 29, 2013. [Photo/Agencies]