First lady Michelle Obama met with former South African President Nelson Mandela on Tuesday as part of a weeklong visit to the continent, according to a spokeswoman for the first lady.

Accompanying her on her visit with Mandela were a nephew, Avery Robinson, 19, and a niece, Leslie Robinson, 15, children of Obama's brother, Craig Robinson, according to Semonti Stephens, deputy communications director for the first lady.

Obama also was expected to visit other luminaries in the country Tuesday after arriving in Pretoria Monday night.

The first lady's trip highlights the value of South Africa as a viable partner with the United States in issues other than politics, said John Campbell, who holds the Ralph Bunche chair in African Policy Studies at the Council on Foreign Relations.

"What is significant about the trip is that it underscores the fact that South Africa, since the establishment of nonracial (politics) has had a string of credible elections, is a country characterized by the rule of law, and is a democracy," Campbell said. "Twenty-five years ago I think relatively few of us would have predicted such a happy outcome."

Obama is scheduled to visit several historical sites, including Robben Island, where Mandela was held for much of his 27-year imprisonment in his fight against apartheid.

Obama, traveling on what officials have said is her second solo official visit to the continent, has brought her daughters, Sasha and Malia, and her mother in addition to her niece and a nephew.

ALIYAFANYA HAYA PIA..................

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"One of the things bringing them along demonstrates is the closeness of the Obama family," Campbell said. "And this is something that the people of Africa respond very well to. Certainly before her, Laura Bush made a number of trips to Africa as well and was very well received."

The visit will further raise the profile on the continent of the first lady and the president, whom many Africans regard as a favorite son.

"The Obamas as a couple are extremely popular in Africa and obviously 100% well-known there," Steve Howard, director of African studies at Ohio University, said Tuesday. "Her husband can't spend that much time there so they are dividing the labor, and she is representing them in South Africa, which is a major media market as well."

Howard said Michelle Obama's visit especially will resonate with the nation's youth.

"It has an enormous young population, probably more than 60% of the population is under 18," Howard said, "and they have a lot of health-related issues, particularly AIDS, and so everything she does there will help bring attention to global health issues."

She is also expected to visit Nobel laureate Archbishop Desmond Tutu as well as Soweto, just outside Johannesburg.

In addition to visits with top leaders, Obama will be a distinguished guest at several public events, meet embassy officials and take part in community service projects in both South Africa and Botswana.

"The trip is a continuation of Mrs. Obama's work to engage young people, especially girls and young women, at home and abroad," the White House said.

Her visit to neighboring Botswana on Friday will include attending a tribute to girls overcoming obstacles as well as a luncheon with women leaders.

She will also meet with President Ian Khama before retreating to a local game reserve for the weekend. After a safari, she is scheduled to depart from the Botswana capital of Gaborone on Sunday.