Mandela celebrates 91st birthday quietly

JOHANNESBURG, South Africa, July 18 (UPI) -- Former South African President Nelson Mandela is determined to keep a low profile Saturday as the world celebrates his 91st birthday, a spokesman said.

The Nobel Peace Prize winner, who fought the country's apartheid regime and become South Africa's first black president in 1994, would spend the day quietly, "with friends, family and comrades," as his backers marked with the launch of a new charitable initiative called Mandela Day, a spokesman told the British newspaper The Guardian.

To celebrate the occasion, the Nelson Mandela Foundation has called on the public to honor his 67-year career in serving the country by devoting 67 minutes to charitable causes.

Mandela's wife, Graca Machel told CNN the elder statesman remains active in working with his charities despite dealing with physical infirmities that have made him too frail to travel overseas for the New York kick-off of Mandela Day, which will feature a Radio City Music Hall concert with Stevie Wonder and Aretha Franklin.

"(Mandela) is a very proud person. He is vain so when he realizes that he can't walk tall and firm like he used to be, he doesn't like it," Machel told the U.S. broadcaster.