The US has formally declared that the military in Niger had staged a coup, cutting off more than $500m (£407m) in aid.
In July the army ousted President Mohamed Bazoum - an ally of Western nations in the fight against jihadist insurgents.
Under US law, a formal designation of a coup requires that aid is suspended.
The US state department said assistance to Niger would only be resumed if the coup leaders ushered in a democratic government.
It is understood that Washington will keep its troops in Niger for the time being.
A US official said the troops were no longer actively helping Nigerien forces but would continue to monitor threats from jihadists.
Earlier France began withdrawing its troops.
BBC