Nelson Mandela remains in hospital, condition "unchanged," South African president says Updated at 7:00 a.m. JOHANNESBURG Former President Nelson Mandela's condition remains serious but stable on Monday, his third day in a Pretoria hospital, the South African government said. "His condition is unchanged," the office of President Jacob Zuma said in a brief statement. Why Nelson Mandela has had frequent hospitalizations recently Mandela, who is 94 years old, was taken to a hospital early Saturday to be treated for a recurring lung infection. At that time, Zuma's office described the anti-apartheid leader's condition as "serious but stable." On Sunday, members of Mandela's family were seen visiting the hospital where the anti-apartheid leader and Nobel Peace Prize laureate is believed to be staying. Mandela, also known by his clan name Madiba, has been hospitalized several times in recent months. During a hospital stay that ended April 6, doctors diagnosed him with pneumonia and drained fluid from his chest. "President Jacob Zuma reiterates his call for South Africa to pray for Madiba and the family during this time," the presidential statement said. Speaking Monday to CBS News correspondent Debora Patta, Zuma's spokesman Mac Maharaj, a longtime friend of Mandela, said the former leader's hospitalization and the fact that he had apparently not improved significantly was undeniably cause for concern, but he cautioned against "reading into it too much." "The doctors have to remain balanced in this situation," Maharaj told Patta. They cannot raise our hopes without justification. Nor can they make us lose hope without justification. Very few people were being permitted to visit Mandela in the hospital, which Maharaj said was normal given the elderly statesman's condition. "We want to give every opportunity for the doctors and the medical team to do their work, unimpeded," said Maharaj. As a patient under intensive care, the normal rules apply. The closest of relatives -- a very limited number -- are allowed to visit. President Zuma will visit when he feels the time is appropriate. On April 29, state television broadcast footage of a visit by Zuma and other leaders of the ruling African National Congress to Mandela's home. Zuma said then that Mandela was in good shape, but the footage - the first public images of Mandela in nearly a year - showed him silent and unresponsive, even when Zuma tried to hold his hand. Mandela has been particularly vulnerable to respiratory problems since contracting tuberculosis during 27 years as the prisoner of the white racist government. The bulk of that period was spent on Robben Island, off the coast of Cape Town where Mandela and other prisoners spent part of the time toiling in a stone quarry. Mandela was freed in 1990 and won election to the presidency in the country's first all-race elections in 1994. He was seen by many around the world as a symbol of resolve and reconciliation for his sacrifice in confinement as well as his peacemaking efforts during the tense transition that saw the demise of the apartheid system. The former leader retired from public life years ago and had received medical care at his Johannesburg home until his latest transfer to a hospital.