The announcement was made just hours after the junta said they were open to dialogue with West African nations to resolve the crisis.
Niger's military that toppled Mohamed Bazoum has said it will prosecute the deposed president for treason.
The announcement was made by a coup spokesperson on national television just hours after the junta said they were open to dialogue with West African nations to resolve the regional crisis.
"The Nigerien government has so far gathered the necessary evidence to prosecute the deposed president and his local and foreign accomplices before the competent national and international bodies, for high treason and undermining Niger's internal and external security, following his exchanges with nationals, foreign heads of state and heads of international organisations," said Col. Major Amadou Abdramane.
The announcement said high-ranking West African politicians and “their international mentors” have made false allegations and attempted to derail a peaceful solution to the crisis in order to justify a military intervention.
It said Bazoum was being charged following his exchanges with these people. The statement did not identify specific Western countries and did not specify a date for the trial.
Niger's democratically-elected president was ousted by members of his presidential guard on 26 July. He has since been under house arrest in the capital, Niamey.
If found guilty, Bazoum could face the death penalty, according to Niger’s penal code.
West Africa's ECOWAS regional bloc has ordered the deployment of a standby force and imposed economic sanctions - which the junta has denounced as "illegal, inhumane and humiliating."