As concern mounts over the political stability of Chad, The Economic Community of Central African States met on Friday in Brazzaville.
The leaders of Congo, Angola, the Central African Republic and the DRC some of the members in attendance.
"The Chadian transition needs the support of all. It will succeed first and foremost with the thinking, intelligence and creativity of Chad's political and military elites," said Moussa Faki, chairperson of the African Union Commission.
"(We) call on all political actors and all active forces in Chad to bear in mind the higher interest of the nation and the good of the Chadian people, and to cooperate sincerely and effectively in order to achieve the objectives of the political transition within 18 months," said Congolese foreign minister Jean-Claude Gakosso.
Chad has a transitional government after the death of longtime leader president Idriss Deby Itno, who was killed in April, according to the army in combat against rebels in the north of the country.
Just a day later his son Mahamat Idriss Deby took over as the transitional leader.
Chad's new leader has promised elections in 18 months.
But the security situation in the country is fragile and the politcal scene is tense, causing concern chaos could spread in the region.