Niger's army command on Thursday declared its support for a coup instigated the previous day by soldiers of the presidential guard, saying its priority was to avoid destabilising the country.

The army needed to "preserve the physical integrity" of the president and his family and avoid "a deadly confrontation... that could create a bloodbath and affect the security of the population," it said in a statement signed by the army chief of staff.

President Mohamed Bazoum and Foreign Minister Hassoumi Massoudou earlier urged democratic forces in the country to resist the power grab, as western officials said the status of the coup attempt was unclear.

The soldiers said in a late-night televised address that Bazoum had been stripped of power and the republic's institutions been suspended, marking the seventh coup in West and Central Africa since 2020.

They earlier cut off the presidential palace in the capital Niamey, with the president inside.

Bazoum, in a social media posting on Thursday morning, vowed to protect "hard-won" democratic gains in a country that is a pivotal ally for Western powers helping fight an insurgency in the Sahel region.

Massoudou also called on "democrats and patriots" to make the "attempted coup" fail, according to a posting on X, the platform formerly known as Twitter.

Niamey was quiet on Thursday morning as citizens awoke to heavy rain, closed borders and a nationwide curfew imposed by the coup instigators.

Massoudou said not all of the army was involved in the coup attempt, and a number of Western officials, speaking on condition of anonymity, told Reuters there was no evidence on the ground that the armed forces supported it.