West African defence chiefs were set to wrap up discussions about possible intervention in Niger on Friday, as mediators from the regional bloc push coup leaders in Niamey to restore constitutional order before an approaching deadline.

The military junta in Niger is locked in a standoff with the Economic Community of West African States (ECOWAS), which has taken its hardest stance yet on last week's ouster of President Mohamed Bazoum - the seventh coup in West and Central Africa since 2020.

In a blow to hopes of restoring the previous status quo, the junta revoked a raft of military cooperation agreements with France late on Thursday. There was no immediate response from France.

The move echoes similar moves by juntas in neighbouring Mali and Burkina Faso in the wake of their coups and could drastically reshape a joint fight against an Islamist insurgency.

France has between 1 000 and 1 500 troops in Niger, helping to fight an insurgency by groups linked to al Qaeda and Islamic State that has destabilised West Africa's Sahel region.

An ECOWAS delegation is in the Nigerien capital Niamey, hoping to secure "a conclusive and amicable resolution" to the crisis, although the bloc has also imposed sweeping sanctions and warned it could authorise the use of force if Bazoum is not reinstated by Sunday.

Niger's self-declared leader Abdourahamane Tiani has rejected the sanctions and said the junta will not back down against any threats.

Later on Friday, the region's defence chiefs will officially end a multi-day meeting in the Nigerian capital Abuja about a possible military response that they have said would be a last resort.

The junta on Thursday said any aggression or attempted aggression by ECOWAS would be met with an immediate riposte on any ECOWAS member-state except those friendly to Niger.

Tiani has won the backing of the juntas in Mali and Burkina Faso and cited persistent insecurity as his main justification for seizing power, even though data on attacks shows that security there has actually been improving.