Italy will stand by South Africa, says Letta
Italian premier says Mandela lesson for Europe10 December, 11:13
"It was a moral obligation to be here," said Letta.
The Italian premier is among over 90 international leaders, including United States President Barack Obama, taking part in the commemoration for Mandela, who died aged 95 last week.
The start of the ceremony was delayed by heavy rain that made it difficult for people to reach the Soweto stadium where it was being held.
A State funeral will be held on Sunday.