General Abdourahamane Tchiani emerged as Niger's new leader following a military mutiny, state TV said.
The chief of the presidential guard has been appointed "president of the National Council for the Safeguard of the Homeland," a statement said, while elected President Mohamed Bazoum has been in the custody of army mutineers since Wednesday morning.
Earlier, Niger's military said on national television that President Mohamed Bazoum had been ousted, borders closed and a curfew declared.
Prior to that, the military of the presidential guard blocked the presidential palace in the capital Niamey.
The president's position was articulated in his remarks on Thursday, in which he noted that democracy would prevail.
The developments in Niger sparked condemnation from UN Secretary-General Antonio Guterres, who urged Bazoum's immediate and unconditional release.
The Russian Foreign Ministry, commenting on the mutiny, said that Moscow is following it "with great concern" and is calling for a peaceful resolution of the crisis for the sake of the country's people.
Earlier in the day, Chairman of the Commission of the African Union Moussa Faki Mahamat told Sputnik that mediators from Nigeria were in Niger for talks with the rebels.