The United Nations on Friday slammed the generals who have seized power in Niger on "a whim" and plunged the country further into misery, demanding that constitutional order be immediately restored.
"The very notion of freedoms in Niger is at stake," UN rights chief Volker Turk said in a statement.
"Generals cannot take it upon themselves to defy -- at a whim -- the will of the people," he said. "Rule-by-gun has no place in today's world."
His comments came after last month's coup toppled Niger's democratically elected president Mohamed Bazoum.
Bazoum, 63, was detained on July 26 by members of the presidential guard, in the fifth coup to hit Niger since independence from France in 1960.
Landlocked Niger has thus joined neighbours Mali and Burkina Faso to become the third Sahel country in three years to experience coups.
Turk highlighted that Niger was already one of the poorest countries in the world, with nearly half of the population "mired in extreme poverty".
He warned that the coup was further worsening the situation, with borders closed, trade at a standstill and severe power cuts and rising food prices, and called for "full and free access for humanitarian assistance".
Turk lamented that "the very people who they elected to build a pathway to end their destitution have been removed by force against the constitutional order and detained by the coup leaders," he said.
"They must be released at once, and democracy restored."
Turk raised concerns about the announced decision by coup leaders to prosecute Bazoum.
"This decision is not only politically motivated against a democratically elected President but has no legal basis as the normal functioning of democratic institutions have been cast aside," he said.
He also described "a clampdown on civic space," pointing to allegations of intimidation against journalists and bans on international media outlets, as "very worrying".