Nelson Mandela, one of the world's most revered statesmen and the icon of the anti-apartheid movement, has marked his 90th birthday by calling for the rich to do more for the poor.

Mr Mandela said he was fortunate to have reached 90, but that many of the poor were unlikely to live that long.

Jailed for 27 years for his part in the African National Congress (ANC) campaign against white minority rule, he emerged to become South Africa's first black president.

His fellow Robben Island prisoners, former jailers and friends joined in celebrations marking his birthday.

The ANC is displaying two huge banners of Mr Mandela on the side of its headquarters, Luthuli House, in Johannesburg.

Nelson Mandela has become South Africa's highest-profile ambassador, campaigning against HIV/Aids and helping to secure his country's right to host the 2010 football World Cup.

In 2004, at the age of 85, Mr Mandela retired from public life to spend more time with his family and friends, and engage in "quiet reflection".