The African Union (AU) has called for a democratic transition in Chad within 18 months following last month’s military takeover.
The AU said it categorically rejected any extension of the transition period.
Chad’s military council has promised to hold elections within 18 months.
It is headed by the son of the former president, Idriss Déby, who died last month after being injured fighting rebels.
There have been regular opposition protests since the military took over, with dozens of activists arrested.