JOHANNESBURG — South Africa's former President Nelson Mandela is suffering from a recurring lung infection and is responding to medical treatments, the nation's presidency said Tuesday.

The ailing Mandela, 94, has been hospitalized since Saturday for medical tests at 1 Military Hospital near South Africa's capital, Pretoria.

The announcement ended speculation about what was troubling the ailing anti-apartheid icon. Government officials had declined repeatedly to say what caused the nation's military, responsible for Mandela's care, to hospitalize the leader over the last few days. That caused growing concern in South Africa, a nation of 50 million people that largely reveres Mandela for being the nation's first democratically elected president who sought to bring the country together after centuries of racial division.