Former South African President Nelson Mandela underwent a diagnostic procedure in a Johannesburg hospital Saturday for a “long-standing” abdominal condition.

The country's current president, Jacob Zuma, said in a statement that the 93-year-old anti-apartheid icon was in no danger and is expected to leave the hospital Sunday or Monday.

Using Mr. Mandela's affectionate clan name, Mr. Zuma's statement read, “Madiba is fine and fully conscious and the doctors are satisfied with his condition.”

A presidential spokesman said the Nobel Peace Prize winner's condition needed “proper specialist medical attention” and added:

“And we are wishing him speedy recovery, assuring him of the love and good wishes of all South Africans and people throughout the world. In the meantime we are requesting from the public to respect the privacy of Madiba and that of his family during this period.”

An African National Congress party spokesman said there is “no need to worry” and that Mr. Mandela's treatment was planned.

Nelson Mandela was imprisoned for 27 years until he was freed in 1990. Four years later he became South Africa's first black president, ending the country's era of apartheid rule.