Presidency: Mandela in critical condition
"The condition of former President Nelson Mandela, who is still in hospital in Pretoria, has become critical," presidency spokesperson Mac Maharaj said in a statement.
He said President Jacob Zuma and ANC deputy president Cyril Ramaphosa visited Mandela on Sunday evening.
"They were briefed by the medical team who informed them that the former president's condition had become critical over the past 24 hours."
Zuma and Ramaphosa also met with Mandela's wife Graça Machel to discuss Mandela's condition.
"The doctors are doing everything possible to get his condition to improve and are ensuring that Madiba is well-looked after and is comfortable," Zuma was quoted as saying in a statement.
"He is in good hands."
Zuma has appealed to South Africans to continue praying for Mandela as well as the medical team that is attending to him.
On Saturday, the presidency confirmed that the military ambulance that transported Mandela to hospital two weeks ago broke down due to "engine problems".
"All care was taken to ensure that Madiba's medical condition was not compromised by the unforeseen incident," said Maharaj.
"Doctors attending to Madiba are satisfied that the former president suffered no harm during this period."
Mandela (94) was hospitalised in the early hours of June 8 with a recurring lung infection.
On Friday, United States-based CBS News reported that Mandela's liver and kidneys were functioning at 50%, and that the ailing former statesperson had two procedures, one to repair a bleeding ulcer and another to insert a tube.
According to the report, Mandela had not opened his eyes in days and was unresponsive.
However, Maharaj said the presidency has been the "source for authoritative reporting on Mandela's health".
'We avoid clinical details'
"Our reports are based on the reports we receive from doctors. We avoid clinical details because we want to ensure no transgression into the privacy of Mandela and his family is ensured," Maharaj said.
"The presidency needs to ensure the dignity of the former president and need to ensure the circumstances are not surrounded by undignified speculative reports." He said Mandela remained in a serious but stable condition in hospital.
The ANC said on Saturday that the presidency had been consistent in keeping South Africa and the world informed of Mandela's health condition.
"The presidency has been consistent and reliable in ensuring that the nation and the world is kept informed on developments relating to our beloved statement and icon, Comrade Nelson Mandela," spokesperson Jackson Mthembu said.
"The ANC has no doubt that the reports they provide are indeed sufficient to ensure that, while respecting the privacy of the former president and his family, we are all kept up-to-date and knowledgeable about his condition within the confines of medical ethics and doctor-patient confidentiality."
Mthembu said the ANC have no doubt that Mandela continued to receive the "very best medical care and attention". – Sapa.