She arrived at Waterkloof Air Force Base in Pretoria at 9.15 pm (1915 GMT).

Obama is expected to be accompanied by her daughters, Malia and Sasha, and her mother, Marian Robinson — but not her husband, US President Barack Obama.

She is scheduled to meet Nompumelelo Ntuli-Zuma, one of South African President Jacob Zuma’s wives, in Pretoria on Tuesday morning before heading for the Nelson Mandela Foundation in Johannesburg, where she will get a tour from the former president’s wife, Graca Machel.

On Tuesday afternoon, Obama will visit a daycare centre in Johannesburg and tour the Apartheid Museum, which chronicles the history of the struggle against white-minority rule.

The six-day trip will also take the first lady to Cape Town and the Botswana capital Gaborone.

Obama has a packed schedule that includes a safari in Botswana, a meeting with Nobel Peace Prize laureate Desmond Tutu in Cape Town and a trip to the memorial for Hector Pieterson — a 12-year-old boy killed in the anti-apartheid Soweto uprising of 1976.

She will also give the keynote address at a conference of the Young African Women Leaders Forum, a two-day meeting of 75 women aged 16 to 30 who play leadership roles across the continent.

The trip is Obama’s second to sub-Saharan Africa, after a 24-hour stop in Ghana with her husband in 2009, and her first solo trip to the continent.