Nelson Mandela now in critical condition, but South Africa gov't remains tight-lipped on circumstances

UPDATE: Former President Nelson Mandela has died at 95

"The doctors are doing everything possible to get his condition to improve and are ensuring that Madiba is well-looked after and is comfortable. He is in good hands," Zuma said in the Sunday statement, using Mandela's clan name.

Zuma also met Graca Machel, Mandela's wife, at the hospital in Pretoria and discussed the former leader's condition, according to the statement. Zuma was accompanied on the visit by Cyril Ramaphosa, the deputy president of the country's ruling party, the African National Congress.

At a news conference in Johannesburg on Monday morning, Zuma would not be drawn further by questions seeking more detail on Mandela's condition.

Zuma said that when he and Ramaphosa arrived late in the day, Mandela "was already asleep."

"We were there, we looked at him, saw him, and we had a discussion with the doctors and with his wife, and we left," said Zuma, adding that he could not provide any further detail because, "I am not a doctor."

Until Sunday, the South African government and members of Mandela's family had issued multiple statements suggesting Mandela was not only stable, but that he was in fact doing "well" -- even suggesting hoped he

CBS News correspondent Mark Phillips reported, however, that according to CBS sources, Mandela's health had actually been in decline since he was admitted to the hospital for a recurrence of lung infection. CBS News has reported that his condition has in fact become further complicated, and that he has been unresponsive and suffering from significant impairment of other vital organs.

With Sunday's statement from President Zuma's office, acknowledging a more dire situation than the "serious but stable" prognosis given for two weeks, "hope is severely diminished," said Phillips.

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Mandela was jailed for 27 years under white racist rule and released in 1990. He then played a leading role in steering the divided country from the apartheid era to democracy, becoming South Africa's first black president in all-race elections in 1994. He was hospitalized on June 8 for what the government said was a recurring lung infection.

In Sunday's statement, Zuma also discussed the government's acknowledgement a day earlier that an ambulance carrying Mandela to the Pretoria hospital two weeks ago had engine trouble, requiring the former president to be transferred to another ambulance for his journey. Pretoria, South Africa's capital, lies about 30 miles from Johannesburg, where Mandela has been living.

CBS News

"There were seven doctors in the convoy who were in full control of the situation throughout the period. He had expert medical care," Zuma said. "The fully equipped military ICU ambulance had a full complement of specialist medical staff including intensive care specialists and ICU nurses. The doctors also dismissed the media reports that Madiba suffered cardiac arrest. There is no truth at all in that report."

"His health was not compromised," insisted Zuma at Monday's news conference, again answering questions about the delay.

Mandela, a Nobel Peace Prize laureate, is seen by many around the world as a symbol of reconciliation, and Zuma appealed to South Africans and the international community to pray for the ailing ex-president, his family and the medical team attending to him.

The ruling party expressed concern about the deterioration in Mandela's health.

"We welcome the work being done by The Presidency to ensure that South Africans and people of the world are kept informed on the state of Madiba's health," the party said. "The African National Congress joins The Presidency in calling upon all of us to keep President Mandela, his family and his medical team in our thoughts and prayers during this trying time."

In Washington, the White House National Security Council spokeswoman noted the latest reports from the South African government about Mandela's worsening condition.

"Our thoughts and prayers are with him, his family and the people of South Africa," said spokeswoman Caitlin Hayden.

Prior to Zuma's statement late Sunday, reports from the government, former President Thabo Mbeki and a grandson of Mandela had indicated that the health of Mandela was improving, even though he has been in the hospital for treatment several times in recent months. In the days following his latest hospitalization, Zuma's office described his condition as serious but stable. Family members have been seen making daily visits to the hospital where Mandela is being treated.

Mandela, who has become increasingly frail in recent years, last made a public appearance at the 2010 World Cup soccer tournament, which was hosted by South Africa. He didn't deliver an address on that occasion and was bundled against the cold in a stadium full of fans.

On April 29, state television broadcast footage of a visit by Zuma and other leaders of the African National Congress to Mandela's home. Zuma said at the time 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.

Between hospital stays in recent months, Mandela has been staying at his home in the Johannesburg neighborhood of Houghton, where he has received what the government described as "home-based high care" by a medical team. On April 6, he was discharged from a hospital after treatment for pneumonia, which included a procedure in which doctors drained fluid from his lung area.

Mandela has been vulnerable to respiratory problems since contracting tuberculosis during his imprisonment under apartheid. Most of those years were spent on Robben Island, a forbidding outpost off the coast of Cape Town.