Former US President Barack Obama delivers his speech at the 16th Annual Nelson Mandela Lecture at the Wanderers Stadium in Johannesburg. Picture: Themba Hadebe/AP

Johannesburg - Barack Obama, the first black president of the United States, opened his speech honouring South Africa's first black president Nelson Mandela by saying that "each day's news cycle is bringing more head-spinning and disturbing headlines."

"Strongman politics are ascendant, whereby elections and some pretence of democracy are maintained while those in power seek to undermine every institution or norm that give democracy meaning," Obama said, just a day after a controversial summit between US President Donald Trump and Russian President Vladimir Putin.

Obama said "those in power seek to undermine every institution ... that gives democracy meaning."

"It is in part because of the failure of governments and elites," Obama said, adding that "we are now returning to a more dangerous way of doing business."

Obama said politicians pushing "politics of fear, resentment, retrenchment" are on the move "at a pace unimaginable just a few years ago."

He added that "the struggle for basic justice is never truly finished."

Obama invokes the World Cup-winning French team and its diversity. "Not all of those folks look like Gauls to me. But they're French!"

"I believe in Nelson Mandela’s vision. I believe in a vision shared by Gandhi and King and Abraham Lincoln. I believe in a vision of equality, justice, freedom and multi-racial democracy, built on the premise that all people are created equal."

“We have to follow Madiba’s example of persistence and of hope.”

“Every generation has the opportunity to remake the world."

IOL, AP, dpa and Reuters