The African Union (AU) has warned against any interference in Niger by those outside of Africa, including private military companies.
This follows a video by Wagner chief Yevgeny Prigozhin, who claimed to be in Africa.
The statement from the AU saying that it was suspending Niger as a member was dated 14 August, but it was only released on 22 August after Mr Prigozhin had published the video.
The BBC has not been able to verify the location of the video. The Wagner boss says he is in 50C (122F) heat, despite appearing to be dressed for cooler weather.
West Africa’s regional bloc Ecowas has said it will send armed forces into Niger to reinstate the democratically elected government.
Western allies of Niger’s deposed president fear the Russian mercenary group, which has been accused of grave human right abuses, could use the crisis there to strengthen its presence in the Sahel – which has become the epicentre of Islamic insurgent violence.
The region has the largest number of terror-related deaths anywhere in the world.
Western and regional forces have struggled to contain the growth of groups affiliated with Islamic State and al-Qaeda, leading to increased attacks on civilians.