In the first announcement about Nelson Mandela's health in past two weeks, South African President Jacob Zuma acknowledged that the leader was gravely ill but has improved over the past few days. Mandela was diagnosed with a lung infection and had gallstone surgery.

It is not the first time that Mandela has had problems with his lungs. In 1988, toward the end of his prison term, Mandela was diagnosed with tuberculosis. Though doctors say that his lungs were not permanently damaged, it is possible for the deadly disease to cause health problems years later.

"His condition was serious but he is responding well to treatment and he steadily improved over the last few days," Zuma said at a conference for the African National Congress, currently the South African government's ruling party. "I've been informed that, at his age, doctors need to intervene in a very gradual and sensitive way in order to maximize the chances of a full recovery. The medical team has our full confidence and he is receiving the best care possible."

The comments are the lengthiest ones that Zuma has made on the matter to date.

This announcement was made 13 days after the anti-apartheid fighter was brought to the hospital. It is the first official acknowledgment that Mandela's condition is grave. Previous comments have been terse and contradictory, as the first comment stated only that the 94-year-old leader was undergoing medical tests. The public announcements have left many to criticize the government's lack of transparency surrounding Mandela's health who remains, for many, a symbol against oppression in South Africa and abroad. After intrusions when Mandela was hospitalized in 2011, the military took responsibility for his care.

Nelson Mandela fought against apartheid in South Africa before spending 27 years in prison for his cause. After his release, he was instrumental in bringing democracy to the country and was elected the first black President of South Africa for a five-year term in 1994. He then retired.

Nelson Mandela has not made a public appearance since the World Cup was hosted by South Africa two years ago. This hospital stay is his longest since he emerged from prison in 1990.