Michelle Obama visits Nelson Mandela at home: official

US First Lady Michelle Obama visited former South African president Nelson Mandela at his home Tuesday during the first full day of a six-day visit to southern Africa, his foundation said.

US first lady Michelle Obama (2ndL), visits the Nelson Mandela Foundation in Johannesburg. Also pictured from L-R: Sello Hatang of the Nelson Mandela Foundation, mother Marian Robinson, Nelson Mandela's wife Graca Machel, and Obama's daughters Sasha and Malia.

Obama, who arrived in South Africa late Monday, visited Mandela's charitable foundation and archives Tuesday and took a tour with the Nobel Peace Prize winner's wife, the humanitarian and former Mozambican first lady Graca Machel.

Obama then paid a "brief courtesy call" on Mandela at his nearby Johannesburg home, said Achmat Dangor, the head of the foundation.

The first lady, who was wearing a coral suit with collarless jacket and a bright print blouse, was accompanied by her mother, Marian Robinson, her daughters, Malia and Sasha, and a niece and nephew.

Mandela, who became South Africa's first black president in 1994 after leading the fight against apartheid, is increasingly frail at 92.

He has been under home medical care since he was hospitalised with an acute respiratory infection in January.

Dangor said the foundation does not comment on Mandela's health, but added: "He must be well enough to receive his visitor".

us first lady Michelle Obama walks with Nelson Mandela's wife Graca Machel as she visits the Nelson Mandela Foundation in Johannesburg, South Africa. Obama visited former South African president Nelson Mandela at his home Tuesday during the first full day of a six-day visit to southern Africa, his foundation said.

The White House has emphasised the importance to the first family of South Africa's struggle against white-minority rule, which President Barack Obama has called his first political cause.

White House officials accompanying the first lady said Mandela's office at the foundation had a photo hanging on the wall of then senator Obama meeting Mandela in 2005.

This was the first lady's first meeting with the anti-apartheid icon.

Obama and her family spent about an hour in Mandela's office with members of his family, then spent some 20 minutes with the foundation's chief historian looking at Mandela's notes and diaries from the 27 years he spent in prison.

The foundation presented the first lady with a soon-to-be-published book of Mandela's quotations.

The foundation said in a statement that Obama expressed appreciation for the display and told employees: "You are doing very important work."