Prime Minister Manmohan Singh Sunday left for a two-nation tour of Nigeria and South Africa to "re-invigorate" India's ties with the African continent and discuss ways to strengthen South-South cooperation. In South Africa, he will attend the second India-Brazil-South Africa (IBSA) Summit that will seek to come up with some concrete proposals to strengthen the trilateral cooperation. Before embarking on the five-day visit, Singh said his journey to Nigeria signifies India's desire to "re-invigorate its ties with not only our friend and brother" Nigeria but the entire African continent. In Nigeria, he will be addressing a joint session of National Assembly, which, Singh said was a "great honor to India". After his two-day stay in Nigeria, Singh will travel to South Africa to attend the second IBSA Summit. "The IBSA process has matured over time. It symbolizes coming together of like-minded countries of Asia, Africa and Latin America for the good of humankind," Singh said about the trilateral forum that now covers a wide range of activities. He said the Summit has a rich agenda and he, along with leaders of Brazil and South Africa, hope to review substantial progress that has been made in expanding our trilateral cooperation. "I expect the Summit to lead to concrete outcomes on both global and trilateral issues," the Press Trust of India quoted the Prime Minister as saying. He will also have bilateral meetings with South African President Thabo Mbeki and Brazilian President Lula da Silva. "India enjoys close and warm relations with South Africa and Brazil which I will seek to further strengthen," he said.