CAPE TOWN - South Africans on Monday were holding their breath over former President Nelson Mandela's health that has deteriorated from serious to critical.

Although Mandela's grandson Mandla Mandela said his family was not ready to contemplate Mandela's death, the whole nation has to prepare for the day without Mandela.

Mandela has been hospitalized for a recurring lung infection since June 8. President Jacob Zuma announced on Sunday evening that Mandela's health "has become critical" in the past 24 hours.

Since then, there has been no new information forthcoming despite intense global interest.

"We are very grateful to the South Africans and the rest of global community for sending him and us messages of support and we are hoping that my grandfather will recover steadly," Mandla said on Monday at the official launch of Mandela School of Science and Technology (MSST) in the Mvezo village, the Eastern Cape Province.

The government has been careful in issuing updates about Mandela's condition.

"We've consistently indicated in the past that his condition was serious; then at one stage we said he was stable. Over the past 24 hours the doctors said (his condition has taken) a downturn and has warranted them saying his condition is critical," the presidential spokesman Mac Maharaj said.

There has been criticism that the government has misled the public about Mandela's health.

The government has given sketchy but positive news about Mandela's condition. On June 16, Zuma said Mandela "continues to get better".

"Over the last two days, although he remains serious, his doctors have stated that his improvement has been sustained," Zuma said.

But the media and public believe that Mandela's condition can be worse than what is officially stated.

"Whenever the government says something, I have to think it twice," said Tshawe Shanteke, who works at a petrol station in central Cape Town. "The whole nation is praying for Mandela's recovery. I cannot imagine the day without Mandela, but we have to prepare for the worst while hoping for the best."

"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 ruling African National Congress (ANC) national spokesperson Jackson Mthembu said.

The ANC "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," Mthembu said.

The presidency has warned against false hope for Mandela's recovery.

In various interviews throughout the morning, Maharaj said the government would continue its policy of not disclosing clinical details but said a "sombre mood" would be appropriate at this time.

In a bid to ease public concern, Mandela's eldest daughter Makaziwe Mandela said on Monday that her father was at peace, and the family hoped for a peaceful transition into the spiritual realm.