He reiterated that “a democratically elected, civilian-led government presents the best opportunity to ensure that Niger remains a strong partner in security and development in the region," US state department spokesperson Matthew Miller said in a statement on Monday.

Mr Bazoum was deposed in a military coup on 26 July and he and his family have since been detained.

The US “called for the immediate release of all those unjustly detained following the military takeover”, Mr Miller said.

The junta, led by Gen Gen Abdourahmane Tchiani, has set up a transitional government and earlier announced a three-year transition period that was rejected by the regional group Ecowas.

Ecowas has been trying to negotiate with the coup leaders and had warned that it was ready to send troops if diplomacy failed.