The West African bloc Ecowas has warned that it risks disintegration and worsened insecurity after Burkina Faso, Mali and Niger formalised their breakaway union.

The head of the Ecowas commission said the move was a major blow to the 50-year-old bloc and could have serious consequences if they do not reverse their decision.

It comes after the military leaders of the three countries said on Saturday that they were "irrevocably" turning their backs on the 15-member Ecowas to form a confederation of their own states.

The juntas came into power after a series of coups between 2020 and 2023, with Ecowas responding by imposing sanctions, demanding a quick restoration of civilian rule.

Ecowas even threatened to use military force, before backing down.

Some of the sanctions have since been removed, and the bloc has been trying to persuade the juntas to drop their threat to leave.

Ecowas says the latest move by the juntas could disrupt the freedom of movement of people across the region and undermine efforts to combat regional insecurity, especially in intelligence sharing.

“Our region is facing the risk of disintegration," Ecowas Commission President Omar Alieu Touray warned on Sunday.

The bloc has appointed Senegalese President Bassirou Diomaye Faye to mediate the crisis.

His appointment was decided at an Ecowas summit held in the Nigerian capital, Abuja, on Sunday.

Mr Faye was touted as having the ability to serve as a facilitator in a mission predicted to face significant challenges.

He is from the same generation as the three military rulers - much younger than the region's other leaders - and shares the juntas' criticism of the role of Western powers in the region, especially France, the former colonial ruler in all four countries.

The three military-led countries have all expelled French soldiers who were there helping to fight jihadist group and turned towards Russia for military assistance.

In a related development, Germany's defence ministry has announced that its army will end operations in Niger at the end of next month following a breakdown of talks with the ruling junta.

It comes after the US completed its withdrawal of troops from an air base in the capital Niamey - leaving its remaining forces at just one drone base in the central city of Agadez.

Nigeria's President Bola Tinubu, who was reappointed as Ecowas chairperson, stressed the need for new partnerships to overcome the political, economic and security challenges of West Africa and the Sahel region in particular - the semi-arid region south of the Sahara Desert.

On Saturday, Burkina Faso, Mali and Niger signed a treaty to form a new confederation - the Alliance of Sahel States.

They agreed to build common institutions and infrastructure that could aid the free movements of their citizens within the three countries.

Ecowas citizens are free to live and work in all members countries but if the three countries left the bloc, their citizens would lose that right, unless a new deal was agreed.

West African leaders fears that jihadist groups could spread through the Sahel borders into neighbouring countries - a situation that might adversely affect their citizens and regional security.

The junta-led states have been worst affected by the Islamist insurgencies, which is one of the reasons the military gave for seizing power.

Adama Gaye, a former Ecowas director of communications, told the BBC that the junta's confederation was a “very big blow” to the bloc as the three are all founding members of Ecowas, which was established in 1975.

However, he partly blamed Ecowas, saying it was pushing the military-led countries to hold free and fair elections, yet several other members were themselves not “true democracies”.

“Ecowas should make an effort to avoid becoming an institutional laughing-stock, because how can you implement this... when most of the other countries claiming to uphold that demand for democracy are not themselves true democracies,” he told the BBC’s Newsday programme.