JOHANNESBURG -- Paying tribute to his personal hero, President Barack Obama met privately Saturday with Nelson Mandela's family as the world anxiously awaited news on the condition of the ailing 94-year-old anti-apartheid leader.
Mr. Obama, who has spoken movingly about Mr. Mandela throughout his trip to Africa, praised the former South African president's "moral courage" during remarks from the grand Union Buildings, where Mr. Mandela was inaugurated as his nation's first black president.
The U.S. president also called on the continent's leaders, including in neighboring Zimbabwe, to take stock of Mr. Mandela's willingness to put country before self and step down after one term despite his immense popularity.
"We as leaders occupy these spaces temporarily and we don't get so deluded that we think the fate of our country doesn't depend on how long we stay in office," Mr. Obama said during a news conference with South African President Jacob Zuma.
Mr. Obama's stop in South Africa marked the midway point of a weeklong trip to Africa, his most significant engagement with the continent since taking office in 2009.
His lack of personal attention on the region has frustrated some Africans who had high expectations for the first black American president and son of a Kenyan man.
Even with Mr. Mandela's health casting a shadow over his visit, Mr. Obama tried to keep focus on an agenda that includes deeper U.S. economic ties with Africa. The president dismissed suggestions that he was only investing personal capital on Africa's economy now as a response to the increased focus on the continent by China, India, Brazil and others.
"I want everybody playing in Africa," he said. "The more, the merrier."
But the president pointedly called on Africans to make sure that countries seeking an economic foothold on the continent are making a "good deal for Africa."
"If somebody says they want to come build something here, are they hiring African workers?" Mr. Obama said. "If somebody says that they want to help you develop your natural resources, how much of the money is staying in Africa? If they say that they're very interested in a certain industry, is the manufacturing and value-added done in Africa?"
The president did not specifically single out China, but some African leaders have criticized Beijing for such behaviors.
Mr. Obama's focus on trade and business appeared to be well received in Africa, home to six of the world's 10 fastest-growing economies. The majority of the questions he received from the South African press and later at a town hall meeting with young African leaders focused on U.S. economic interests in the region.
Between his two events, Mr. Obama spent about 30 minutes meeting privately with two of Mr. Mandela's daughters and several of his grandchildren at the former leader's foundation offices in Johannesburg. He also spoke by phone with Mr. Mandela's wife, Graca Machel, who remained by her husband's side at the Pretoria hospital where he has battled a lung infection for three weeks.
In a statement following the call, Ms. Machel said she drew strength from Mr. Obama and his "touch of personal warmth."
Mr. Obama, who has met Mr. Mandela in person only once before, did not visit the former leader in the hospital out of respect for his family's wishes, the White House said. Ahead of his arrival in South Africa, the president had told reporters that he did not need "a photo-op" and didn't want to be obtrusive.
Mr. Obama ascent to the White House has drawn inevitable comparisons to Mr. Mandela. Both are their nations' first black presidents, symbols of racial barrier breaking and winners of the Nobel Peace Prize.
Also Saturday, Mr. Obama held a town hall with young people in Soweto, an area of Johannesburg that was a center of the youth-driven movement to fight against South Africa's apartheid government. At least 176 young people were killed there 27 years ago this month during a youth protest against the white government's ban against teaching local Bantu languages. The Soweto Uprising catalyzed international support against apartheid, and June is now recognized as Youth Month in South Africa.
Outside the event, protesters under police watch demonstrated outside the university against Mr. Obama's record on surveillance and foreign policy. Protesters from a range of trade unions and civil society groups chanted, "Away with intelligence, away," holding posters depicting Mr. Obama with an Adolf Hitler moustache.