Although there were no signs of further violence, armed soldiers were carrying out street patrols, while Niamey was reportedly calm following a night of curfew.
Lydia Addo from RFI's Hausa service, who's in Niamey said, "there is not any problems, everything is okay, people are going up and down, going to the Mosque for their prayers".
Meanwhile, Jean Ping, the chair of the African Union, condemned “any unconstitutional change” on Friday, and called for the “speedy return to constitutional order”.
It is thought 71-year-old Tandja is being held in a barracks on the outskirts of Niamey after Thursday’s ousting.
The military junta, known as the Supreme Council for the Restoration of Democracy (CSRD), called for calm and closed the country’s borders.
Colonel Goukoye Abdul Karim, a spokesperson for the CSRD, said “we have decided to put an end to this tense political situation”.
Tandja had changed the constitution last August in order to allow himself to stay in office.
At least three soldiers were killed on Thursday in gun battles that followed the storming of the presidential palace during a cabinet meeting.