Television announcement came shortly after state election body announced incumbent Ali Bongo had won a third term as president.
A group of senior military officers have appeared on television in Gabon claiming they have taken power because elections held over the weekend were not credible.
The officers said in the Wednesday broadcast they had cancelled the elections, dissolved all state institutions and closed the country’s borders.
They said they represented all security and defence forces of Gabon.
The announcement came shortly after the state election body said President Ali Bongo had won a third term in office in Saturday’s disputed elections.