The African Union has suspended Gabon's participation in all of its activities following Wednesday's military takeover, which it strongly condemned.
The decision followed a meeting on Thursday of the bloc's Peace and Security Council.
Earlier, the Gabonese junta said it would phase in what it is calling transitional institutions after the removal of President Ali Bongo.
The soldiers gave no details on how long these would remain in place nor on how or whether power might be handed back to a civilian government.
The main opposition alliance has urged the junta to discuss the best way forward.
It added that Gabonese should be grateful that they had dethroned the Bongo dynasty but called on the military to act responsibly.
BBC