Former South African President Nelson Mandela urged the leaders of Africa on Sunday to draw lessons from those who liberated the continent from colonialism as they chart paths to lift their countries from poverty and strife.

Mandela, who led South Africa out of the apartheid era, said African leaders who guided their countries to independence offered many lessons to their successors.

Kwame Nkrumah of Ghana and other pioneers demonstrated that "we could challenge colonialism. We are following in their path," he said on arrival in Nairobi, where he was greeted by traditional songs, drumbeats and dances.

"Such leaders have not perished. They are coming up in droves and inspire an entire continent," said Mandela, 87, who appeared frail and was often supported by an aide.

Mandela retired from public life last year. He is visiting Kenya with his wife, Graca Machel, who is in the country to lead meetings on a final report on Kenya in a closely watched African peer review process.

Mandela said Africans should concentrate on the positive achievements their leaders have made and not their failings, as the continent works to solve its own problems.

Kenya is among the first four countries to take part in a peer review plan being closely watched by Africans and international donors and sponsored by the New Partnership for Africa's Development.

The partnership launched the voluntary reviews by African peer countries to encourage more aid and investment into the world's poorest continent by improving governance. Evaluators assess governments' records in democracy, human rights, peace and security, economic policy and business environment.

On his arrival in Nairobi, Mandela was greeted at Jomo Kenyatta International Airport by Elsie Mukami, wife of the executed Mau Mau revolutionary leader, Dedan Kimathi.

Kimathi's fight for Kenya's independence in the 1950s made him an icon of Africa's struggle for freedom among Mandela's generation of activists.