The African Union on Thursday called for civilian and military leaders in Chad to share power until elections can be organised following the death of President Idriss Deby and subsequent military takeover last month.

While the AU repeated its earlier calls for a civilian-led transition to elections after 18 months, it said the military officers that seized power, led by Deby's son Mahamat, could continue to oversee security matters.

In a statement, the AU's Peace and Security Council "underscored the imperative of an inclusive and consensual transition process in Chad run by civilians, with a clear separation of roles and functions between the transitional government and Transitional Military Council (CMT)".

A CMT spokesman said he welcomed the AU's recommendations.

"The division of tasks will be done clearly and pragmatically so that everyone goes to work to meet Chadians' expectations for peace and free and peaceful elections," General Azem Bermandoa Agouna told Reuters.

Idriss Deby had ruled Chad, an important ally of France and other Western powers in the fight against Islamist militants, for 30 years. His death while visiting troops fighting a rebel insurgency in the north raised fears of regional instability.

As a result, analysts said, AU leaders have taken a softer line than they ordinarily would have following a military takeover by declining to say a coup had occurred or impose sanctions.

On Tuesday, Democratic Republic of Congo President Felix Tshisekedi, chairman of the African Union, backed the military's takeover, saying the risk of disorder made its "firm hand" necessary.

The AU statement also called on Mahamat Deby, who is serving as Chad's interim president, and the other members of the CMT to respect their promises not to run for office in elections next year.

Since taking over, the military has appointed a new government with many civilian ministers, although most held positions under Idriss Deby, drawing criticism from the opposition.