"Former President Nelson Mandela remains in hospital, and his condition is unchanged," the presidency said in a brief statement on the health of the 94-year-old anti- apartheid icon.
Mandela was shifted to a Pretoria hospital in the early hours on Saturday, the third time this year he has been admitted. In April, doctors diagnosed him with pneumonia and drained fluid from his chest.
"President Jacob Zuma reiterates his call for South Africa to pray for Madiba (Mandela's clan name) and the family during this time," the government said.
Mandela's wife, Graca Machel, cancelled a scheduled appearance in London on Saturday to remain at her husband's bedside.
Yesterday, members of Mandela's family were seen visiting the hospital where the Mandela, Nobel Peace Prize laureate, is believed to be staying.
Mandela served as president from 1994 to 1999.
He was previously imprisoned for 27 years, and is believed to have suffered damaged lungs while working in a prison quarry.
Though Mandela retired from public life in 2004 and has been rarely seen in public since 2010, he remains a towering symbol in South African public life.
