Hillary Clinton meets Mandela

US Secretary of State Hillary Clinton has met Nelson Mandela at his rural homestead where South Africa's first black president is living out retirement far from the public eye.

Her private lunch with the Nobel Peace Prize winner on Monday was the first event of her South African visit, an indication of the prestige still enjoyed by the man who led the fight against white-minority rule.

The two chatted in his home ahead of the meal, an honour that few receive as Mandela's health has become more fragile with age.

Mandela did not speak but smiled as he and his wife, Graca Machel, posed for a picture with Clinton.

'That's a beautiful smile!' Clinton said.

'Madiba's smile is a trademark,' Machel said.

Mandela was elected president in South Africa's first all-race elections in 1994, after spending 27 years as a political prisoner under the segregationist apartheid regime.

Clinton's husband, Bill Clinton, was the US president when Mandela took office. Their two families developed close ties, with Bill Clinton paying a visit to Qunu last month on the eve of Mandela's 94th birthday.

'Madiba not only represents all that there is great in the world, but (is someone) who to the secretary is a close friend ... somebody who she has learned a lot from,' a US official said ahead of the secretary of state's meeting.

While she was meeting Mandela, an American business delegation was holding a trade meeting with South African executives in Johannesburg, the commercial hub of Africa's largest economy.

Members of the American business delegation include senior executives from Black Veatch, Boeing, Chevron, EMD/Caterpillar, FedEx Express, GE, Symbion, Trimble, Wal-Mart, and Zanbato.

A trade mission also includes the heads of the Overseas Private Investment Corporation, the Export-Import Bank of the United States, the US Trade and Development Agency, as well as Robert Hormats, under secretary of state for economic growth, energy and the environment, and ! Francisc o Sanchez, under secretary of commerce for international trade.

Clinton is set to leave South Africa on Thursday for Nigeria and then Benin. She is also expected in Ghana for the state funeral of late president John Atta Mills, before heading to Istanbul for talks on the crisis in Syria.