The South Africa government says Nelson Mandela remains in a serious but stable condition, two days after being admitted to hospital with a lung infection.
"Former President Nelson Mandela remains in hospital and his condition is unchanged," the South African presidency said in a statement on Monday.
The increasingly frail 94-year-old anti-apartheid leader was admitted to a Pretoria hospital early on Saturday.
Updates about his health have been infrequent, and the latest tersely worded report is only likely to fuel concerns about the fate of a man who is regarded as the father of modern South Africa, AFP reports.
"President Jacob Zuma reiterates his call for South Africa to pray for Madiba and the family during this time," the government said.
It is the fourth hospital stay since December for the Nobel peace prize laureate, who turns 95 in July.
Although Mr Mandela has long since left the political stage and has not been seen in public since 2010, he remains a towering symbol in South African public life.
Prayers were said in churches throughout the country for Mr Mandela on Sunday. His daughter, Zinzi Mandela, told reporters after visiting him that her father is a fighter.