Prior to arriving in South Africa, Obama paid tribute to Mandela for the way he led his nation out of apartheid after years of struggle, but said he did not need a "photo op" with the former president, currently critically ill in hospital.

Obama's speech at the University of Cape Town was welcomed as a key address by university leaders.

(SOUNDBITE) (English) MAX PRICE, UNIVERSITY OF CAPE TOWN (UCT) VICE CHANCELLOR, SAYING:

"So his visit is rich, not only with the symbolism and especially at this time with Mandela's failing health and the links with Kennedy, freedom and what Obama represents as the first African American president but also with the future of the continent and a focus on youth."