A West African leaders' summit opens on Sunday amid political turmoil after the military rulers of Niger, Mali and Burkina Faso cemented a breakaway union at a rival meeting.
The three countries announced they were forming a new confederation, and their defiant first gathering on the eve of the Economic Community of West African States (ECOWAS) summit marks another test for the regional bloc they split away from earlier this year.
ECOWAS is already wrestling with sweeping jihadist violence, financial trouble and the challenges of mustering a regional force.
It was not clear how the weakened bloc would respond after Niger, Mali and Burkina Faso adopted a treaty establishing a "Confederation of Sahel States" in Niamey on Saturday.
The juntas in those three countries came to power in a series of coups over recent years and announced their joint departure from ECOWAS in January.
They have shifted away from former colonial ruler France and expelled French troops, with Niger's General Abdourahamane Tiani calling for the establishment of a "community far removed from the stranglehold of foreign powers".
"Our people have irrevocably turned their backs on ECOWAS," General Tiani said on Saturday, rebuffing the bloc's pleas to come back into the fold.
The Sahel countries' ECOWAS exit was fuelled in part by their accusation that Paris was manipulating the bloc and not providing enough support for anti-jihadist efforts.
Sunday's summit in the Nigerian capital Abuja comes after several West African presidents called for the resumption of dialogue.
It will be the first such meeting for Senegal's new President Bassirou Diomaye Faye, who said in May that reconciliation was possible.
Niger's ties with ECOWAS deteriorated following the July 2023 coup that brought Tiani to power, when the bloc imposed sanctions and threatened to intervene militarily to restore ousted president Mohamed Bazoum.
The sanctions were lifted in February but relations remain frosty.
Ahead of the ECOWAS summit, defence and finance ministers have been looking into funding a long-proposed "regional force to combat terrorism and restore constitutional order", according to the ECOWAS Commission.
It called for the establishment of an initial 1,500-strong unit, and one proposal was to then muster a brigade of 5,000 soldiers at a cost of around $2.6 billion a year.
ECOWAS has launched military interventions in the past, but its threat of doing so after the coup in Niger fizzled out.
As the bloc grapples with regional challenges, ECOWAS Commission chief Omar Alieu Touray warned that its "financial situation is dwindling".
Ahead of the summit, he called for "urgent and decisive action to enable ECOWAS to respond to the diverse demands of the day."
There were also reports of a rift over the possible reappointment of Nigerian President Bola Ahmed Tinubu as ECOWAS chair.
Media adviser to the Nigerian president Bayo Onanuga told AFP that "while some countries want him to remain because the region has faced some crisis, the Francophone countries want the seat."
Some French-speaking countries were expected to send their foreign ministers to Sunday's summit instead of their leaders.
Benin's foreign minister told AFP that President Patrice Talon would not be attending "for scheduling reasons" and denied a dispute, saying that Talon supported Tinubu's reappointment.
