Leaders of the West African Ecowas bloc said Thursday they would deploy a "standby force" against the military leaders who seized control of Niger two weeks ago.

The bloc's Commission President Omar Touray said after an emergency summit in Nigeria that members had decided "to order the deployment of the Ecowas standby force to restore constitutional order in Niger".

The details of an eventual deployment and its impact on Niger were not immediately clear.

Ahead of the closed-door summit talks, Nigeria's President Bola Tinubu had insisted that "we prioritise diplomatic negotiations and dialogue" for ending the crisis in Niger.

"All is not lost yet" for a "peaceful solution, as a roadmap to restore democracy and stability," Tinubu said after the meeting.

But he added: "No option is taken off the table, including the use of force as a last resort".

"If we don't do it, no one else will do it for us."

Ivory Coast's President Alassane Ouattara told journalists before leaving the summit that Ecowas "has intervened in the past, in Liberia, in Sierra Leone, in Gambia and Guinea-Bissau" when constitutional order in the countries was threatened.

"Today we have a similar situation in Niger, and I like to say that Ecowas cannot accept this," he said, adding that he hoped the decision to deploy the force "will be implemented immediately". (AFP)