U.S. Secretary of State Antony Blinken spoke on Monday with Niger's President Mohamed Bazoum, who was ousted in a military coup in July, to reiterate Washington's support for the African country's democratically elected government, the State Department said in a statement.

Blinken told Bazoum that a civilian-led government "presents the best opportunity to ensure that Niger remains a strong partner in security and development in the region," the statement said.

Soldiers from the presidential guard detained Bazoum on July 26 and have set up a transitional government, one of a series of recent coups in West Africa's Sahel region.

"The United States calls for the immediate release of all those unjustly detained following the military takeover," the State Department said.