South Africans prepared on Thursday to say farewell to ailing anti-apartheid leader Nelson Mandela after his condition deteriorated further in hospital, forcing President Jacob Zuma to cancel a trip to neighboring Mozambique.

Zuma was due to attend a summit in Maputo of the Southern African Development Community (SADC) to discuss regional infrastructure, but pulled out after visiting the 94-year-old former president in hospital late on Wednesday.

"Over the past 48 hours, the condition of former president Madiba has gone down," presidential spokesman Mac Maharaj told state broadcaster SABC, using the clan name by which Mandela is affectionately known.

Maharaj said Mandela's condition remained critical. He declined to comment on media reports that he was on life report in the Pretoria hospital where he is being treated for a lung infection, saying his privacy should be respected.

Mandela has already spent 20 days in the hospital, his fourth hospitalization in six months.This has forced a growing realisation among South Africans that the man regarded as the father of their post-apartheid "Rainbow Nation" will not be among them for ever. "Mandela is very old and at that age, life is not good. I just pray that God takes him this time. He must go. He must rest," said Ida Mashego, a 60-year-old office cleaner in Johannesburg's Sandton financial district.

Mandela, South Africa's first black president, is admired around the world as a symbol of resistance to injustice for the way he opposed his country's apartheid system, spending 27 years in jail, more than half of them on notorious Robben Island.He is also respected for the way he preached reconciliation after the 1994 transition to multi-racial democracy following three centuries of white domination.

"Celebrating his LIfe"

U.S. President Barack Obama is due to visit South Africa at the weekend as part of a three-nation Africa tour he has already started in Senegal. Maharaj said it was too early to say whether Obama's schedule in Johannesburg and Cape Town on Saturday and Sunday might be affected by Mandela's worsening condition.

Well-wishers' messages, bouquets and stuffed animals have piled up outside Mandela's Johannesburg home and the wall of the hospital compound where he is being treated in the capital. As they headed to work on Thursday, South Africans seemed resigned to the prospect of losing their hero.

"We are all going to feel bad when he passes, but at the same time we will be celebrating his life. He has done so many great things for this country," said John Ndlovu, a 25-year-old office worker.

Mandela stepped down in 1999 after one five-year term in office.Since then he has played little role in public life, dividing his time in retirement between his home in the wealthy Johannesburg suburb of Houghton and Qunu, the village in the impoverished Eastern Cape province where he was born. The public's last glimpse of him was a brief clip aired by state television in April during a visit to his home by Zuma and other senior officials from the ruling African National Congress.

At the time, the 101-year-old liberation movement assured the public Mandela was "in good shape", although the footage showed a thin and frail old man sitting expressionless in an armchair.