Nelson Mandela, South Africa's first black president and a prominent human-rights campaigner, has reportedly undergone treatment for a hernia, according to media reports.

'People need not panic'—Keith Khoza, African National Congress spokesman

Mandela is said to be in a stable condition in hospital after an operation, according to BBC News. The authorities would not divulge what procedure he has undergone.

CNN, quoting a family member, said the anti-apartheid icon underwent surgery to repair a hernia, while the Telegraph said he had a "diagnostic procedure" for a suspected hernia, or weaknesses in the abdominal wall.

“[Mandela] is fine and fully conscious and the doctors are satisfied with his condition, which they say is consistent with his age," South African President Jacob Zuma said in a statement Saturday afternoon.

Zuma said Mandela is expected to be released on Monday.

The 93-year-old Nobel Peace Prize winner had previously battled prostate cancer in 2001 and retired from public life in 2004. He last appeared in public in the closing ceremonies of the 2010 World Cup in South Africa.

Earlier, a spokeperson for the ruling African National Congress tried to tamp down concerns about Mandela, stressing that the hospital visit was planned and was not an emergency. Mandela, who has long complained of abdominal pain, did not require surgery, the official said.

In a statement, the ANC said the government was "satisifed that [Mandela's] condition is not life-threatening, and that the admission was long arranged."

Keith Khoza, a spokesman for the ANC, reiterated that Mandela's abdominal pains are not new.

"People need not panic," Khoza said.

Rarely appeared in public

GRN reporter Tim Butcher, reporting from Cape Town, told CBC News that Mandela was transported from his ancestral home in rural South Africa in Qunu to the capital, Pretoria, for a procedure.

"He has tuberculosis in his lungs, a rebuilt knee, he's had prostate cancer, he's a very frail 93-year-old, so they're taking no risks when it comes to his health," Butcher said.

Mandela's health has declined rapidly in recent years, and he has rarely made public appearances.

The government requested that the former political prisoner be given privacy with his family.

In his earlier life, he was jailed for 27 years for a conviction for sabotage against the government. Upon release, he went on to become the leader of the struggle against racist apartheid rule in South Africa, culminating in his being elected president in 1994. He served one term.

Mandela was hospitalized for several days last year for treatment for an acute respiratory infection.

With files from The Associated Press