The United Nations (UN) on Thursday said Niger’s President Mohamed Bazoum must be released immediately and constitutional order restored.

The UN spoke after elite troops detained Bazoum and declared they had taken power.

Bazoum was confined in Niamey on Wednesday by members of his presidential guard, who hours later announced that “all institutions” in the troubled West African nation would be suspended, the borders closed and a night-time curfew imposed.

“I am shocked and distressed by the attempted military takeover in Niger and condemn it in the strongest terms. All efforts must be undertaken to restore constitutional order and the rule of law,” UN human rights chief Volker Turk said in a statement.

“President Mohamed Bazoum must be immediately and unconditionally released, and his security ensured. The arbitrarily detained members of his government and their relatives must also be released forthwith and without preconditions.

“I urge all actors to refrain from violence and respect the rights and fundamental freedoms of all. It is in the interests of all the people of Niger that the important democratic gains made in recent years are safeguarded and preserved.”

The landlocked Sahel state is one of the poorest and most unstable countries in the world.

Bazoum, 63, is one of a dwindling group of pro-Western leaders in the Sahel, where a rampaging jihadist insurgency has triggered coups against elected presidents in Mali and Burkina Faso.