The new force "will be operational as soon as possible to take into account the security challenges in our space", Niger's army chief Moussa Salaou Barmou said in a statement following talks in Niamey.

"We are convinced that, with the combined efforts of our three countries, we will manage to create the conditions for a shared security," he added.

The size of the joint force was unspecified but Barmou said the three armies had agreed to develop an "operational concept" that would allow them to reach their defence and security objectives.

The announcement is the latest bringing closer the three neighbours, who have severed ties with former colonial ruler and traditional security ally France in favour of Russia.

Last year they joined diplomatic forces in an Alliance of Sahel States with a view to creating a federation and in January announced their intention to withdraw from regional bloc the Economic Community of West African States (ECOWAS).

ECOWAS had imposed sanctions on all three countries for overthrowing democratically elected governments in a succession of coups since 2020.

Anger at civilian governments for failing to stem the violence meted out by jihadist rebels affiliated with Al-Qaeda and the Islamic State group played a large role in the military takeovers.

A jihadist revolt broke out in northern Mali in 2012 before spreading to neighbouring Niger and Burkina Faso in 2015.

The spiralling violence is estimated to have killed thousands and displaced millions across the region.