The Associated Press reports the 93-year-old Nobel peace laureate was released Sunday after undergoing a laparoscopy, a procedure by which "surgeons make an incision in the belly to insert a thin, lighted tube to look at abdominal organs."

South Africa President Jacob Zuma said "doctors have assured us that there is nothing to worry about", according to AP reports.

The world-revered Mandela spent 27 years in prison for protesting against aparthied, the racist and White supremacist-based government that formerly ruled South Africa. He became South Africa's first Black president in 1994 and served for five years. According to AP, he last appeared in public in July 2010.