Johannesburg: Ailing anti-apartheid icon Nelson Mandela is "unstable" at times but has demonstrated "great resilience" as he remains critical in hospital, South Africa`s presidency said on Saturday.
"While at times, his condition becomes unstable, the doctors indicate that the former President has demonstrated great resilience and his condition tends to stabilise as a result of medical interventions," the presidency said.
The 95-year-old former democracy hero was hospitalised in a Pretoria hospital on June 8 with lung infection.
Mandela remains in the Pretoria hospital and his condition is still critical but stable, the statement said.
"Doctors are still working hard to affect a turnaround and a further improvement in his health and to keep the former President comfortable," it said.
President Jacob Zuma asked South Africans to continue praying for Madiba, as Mandela is popularly refereed to, and to keep him in their thoughts at all times.
Mandela had a long history of lung problems, dating back to the time when he was a political prisoner on Robben Island during apartheid. While in jail he contracted tuberculosis.
He is revered for leading the fight against white minority rule in South Africa and then pushing reconciliation despite being imprisoned for 27 years.
Mandela, regarded the founding father of South Africa`s multiracial democracy, served as the country`s first black president from 1994 to 1999. He left power after five years as president.
He was was awarded the Nobel Peace Prize in 1993. He retired from public life in 2004 and has rarely been seen at official events since.