Mandela was hospitalized early Saturday after the state of his health deteriorated in the last few days, according to spokesman Mac Maharaj.
"He's receiving the best possible care," he said. "Everything is
being done to ensure that he is comfortable and that he is getting better."
Maharaj said that the anti-apartheid icon is breathing on his own.
South Africa's first black president gets round-the-clock care, and his house is retrofitted with medical equipment that mirrors that of an intensive care unit.
Mandela, 94, has become increasingly frail over the years and has not appeared in public since South Africa hosted the World Cup in 2010.
Despite his rare public appearances, news of his ailment spark concerns worldwide.
"I think the concern, the anxiety shown by people throughout the world and South Africa is perfectly understandable," Maharaj said. "I think it is also true simultaneously that people have come to terms with his age. The most important thing is that we should realize that this is a life that we need to celebrate, even when he's with us. And we will celebrate it, even when he is not with us."
Look back at Mandela's early years
Mandela has been in and out of hospitals in recent years.
His history of lung problems dates to when he was a political prisoner on Robben Island during apartheid, and he has battled respiratory infections over the years.
Last year, he spent Christmas holidays undergoing treatment for a lung infection and gallstones, one of his longest hospital stays since his release from prison in 1990.
Considered the founding father of South Africa's democracy, Mandela became an international figure while enduring 27 years in prison for fighting against apartheid, the country's system of racial segregation.
"He has taught us ... that we enhance our own humanity when we serve and make a difference to other people's lives," Maharaj said. "It's easy to serve oneself, own interests, but serving the interests of others, making their lives better changes the quality of all humanity."
In 1993, Mandela and then-South African President F.W. de Klerk jointly won the Nobel Peace Prize.
The iconic leader was elected the nation's first black president a year later, serving only one term, as he had promised.
Despite rare public appearances in recent years, he retains his popularity and is considered a hero of democracy in the nation. Last year, South Africa launched a new batch of banknotes with a picture of a smiling Mandela on the front, a testament to his iconic status.
Mandela's impact extends far beyond South African borders. After he left office, he mediated conflicts from Africa to the Middle Eas