Millions of South Africans are celebrating the birthday of Nelson Mandela, who turned 93 Monday.

South African schoolchildren began their day by singing a special birthday song for Mr. Mandela, while many adults heeded his call to mark the day by performing community service.

The anti-apartheid icon celebrated with family and friends at his home in the town of Qunu. South African President Jacob Zuma was due to pay him a visit later in the day.

In a statement, President Zuma said Mr. Mandela “laid the foundation” for a solid democracy in South Africa, but that more work still needs to be done to address poverty and improve the lives of children.

U.S. President Barack Obama called Mr. Mandela “a beacon for the global community, and for all who work for democracy, justice and reconciliation.”

The Nobel Peace Prize laureate led the struggle to bring down South Africa's system of white minority rule and discrimination against blacks. In 1994, he became the country's first black president.

The United Nations designated the former leader's birthday as Nelson Mandela Day in 2009, with a call for individuals to do 67 minutes of community service to represent the number of years he spent in politics.