QUNU, South Africa  - South Africa's schoolchildren sang happy birthday to anti-apartheid hero Nelson Mandela who turned 94 on Wednesday, joining in the global praise for the much-loved statesman.

Mandela, whose 1990 release from an apartheid prison put South Africa on the path to democracy and reconciliation, spent a quiet day with his close family in his home village of Qunu, where he has retired from public life. The nation's 12 million schoolchildren began their day with a special birthday song for the Nobel Peace Prize laureate, ringing with the line: "We love you father". "As we celebrate his birthday, we remember that he fought for us in the struggle. The struggle was to fight apartheid," said 12-year-old Kgaugelo Masunhloane at Batsogile primary school in Soweto. "He spent 27 years in prison. We would want to say thank you Madiba, and we wish you happy birthday, and many more years to come."
Mandela, known fondly by his clan name Madiba, has not appeared in public since the World Cup in 2010. But his relatives said he was doing fine, for a man of 94. Chief Mandla Mandela, the family's head, he was "relaxing at home and doing fine" at his Qunu home. "Generally, he's looking good and he's joking, he's his old self," his granddaughter Tukwini Mandela told CNN from the family compound.
Images of Mandela have become rare since he retired to Qunu. But he retains the ability to inspire, and for many South Africans remains a symbol of the best of themselves, for leading the nation away from civil war and to a non-racial democracy.
Former US president Bill Clinton met Mandela at his village home on Tuesday. A photograph released after the meeting showed Mandela seated in an armchair, his lap covered by a blanket, as he held Clinton's hand. A couple of buses and a few dozen cars were parked outside his home where entry was restricted to his close family members. Villagers at his birthplace in nearby Mvezo were showered with gifts, including wheechairs donated to the only clinic in the village. But fellow Nobel peace laureate Archbishop Desmond Tutu warned that South Africa was not living up to Mandela's ideals, saying he would be shocked at the shambolic state of public schools.
"If he (Mandela) knew what was happening he would be crying... it's totally unacceptable," Tutu told a leadership summit in the central Free State province.
Mandela was born on July 18, 1918 in a Thembu royal family in Mvezo village southeastern South Africa.
US President Barack Obama and his wife, Michelle Obama, paid tribute to Mandela ahead of his 94th birthday, as having "abiding humility" and "unbreakable will."
"On behalf of the people of the United States, we would like to extend our heartfelt congratulations to Nelson Mandela on the occasion of his 94th birthday and the fourth annual Nelson Mandela International Day," the US first couple said in a statement honoring the antiapartheid icon.
Mandela's "extraordinary life and steadfast commitment to the principles of democracy and reconciliation continues to be a beacon for people of all backgrounds who strive for dignity, justice, and freedom," they said, describing his personal story as "one of unbreakable will, unwavering integrity, and abiding humility.
The Obamas said their family "has been inspired by Madiba's example, and has deeply appreciated the time we have spent with him, and his wisdom, grace and generosity of spirit."
"By any measure," the statement read, "Nelson Mandela has changed the arc of history, transforming his country, continent, and the world."
The US first lady met with Mandela June 11, 2011 on a visit to South Africa with her daughters.
Obama's Democratic predecessor Bill Clinton meanwhile hailed his close ties with Nelson Mandela before visiting Mandela's home in his childhood village.
Clinton spent two hours inside Mandela's family compound in Qunu, the picturesque south-eastern village where the South African leader grew up.
Media were barred from entering the area and Clinton left without speaking.
Before the visit Clinton opened a library at a primary school together with Mandela's wife, Graca Machel, and daughter Zindzi ahead of the statesman's birthday Wednesday.
"We worked together as presidents and even after we left office we continued working together to improve education of the children worldwide in order for them to share the future," Clinton said.
Mandela, who was president from 1994-1999, spent 27 years in the apartheid regime's jails. He retired from political life in 2004.