Russia has warned that military intervention in Niger would lead to a “protracted confrontation” after regional bloc Ecowas said it would assemble a standby force.
Such an intervention would destabilise the Sahel region as a whole, the Russian foreign ministry said.
Russia does not formally back the coup.
But the US, which backs efforts to restore deposed leader Mohamed Bazoum, says its Wagner mercenary group is taking advantage of the instability.
On Friday coup supporters, some waving Russian flags, protested at a French military base near the capital NIamey, some chanting “down with France, down with Ecowas”.