It said the condition of Keita, 75, was not immediately known.
It was not clear either if he would be taken abroad for treatment.
A mutiny in Mali began on 18 August at a military base near the capital of Bamako. Mutineers said they had arrested President Keita and Prime Minister Boubou Cisse. Keita subsequently announced his resignation and the dissolution of the government and parliament.
The mutineers called for a political transition in the country and general elections. In a statement released on 20 August, the coup organizers said that a specially appointed president, who can be either military or civilian, would rule Mali during the transition period.