Leaders from the West African bloc ECOWAS on Sunday admitted during talks in the Nigerian capital that the region was in trouble, facing mounting unrest and political instability.

"Our region is at the crossroads," said Sierra Leone's Julius Maada Bio as he took over the rotating chairmanship of the Economic Community of West African States (ECOWAS) from Nigeria's Bola Tinubu.

West Africa is "facing serious challenges, some long-standing, others new and evolving", he said.

They included "insecurity in the Sahel and coastal states, terrorism, political instability, illicit arms flow and transnational organised crimes".

It was time to "overhaul our collective security architecture", including intelligence-sharing and rapid response, he added. "The democratic space is under strain in parts of our region -- the constitutional order has been disrupted."

Coups and attempted putsches have rocked nearly half of the original ECOWAS member states in the last decade, straining relations between neighbours.

Three junta-led countries -- Mali, Burkina Faso and Niger -- quit the bloc earlier this year, setting up their own bloc.

Jihadists exploiting strained relationships between regional countries are gaining ground in the Sahel and Lake Chad region.

They have recently have intensified offensives in the Sahel region, staging bloody raids in Mali, incursions into major cities in Burkina Faso and inflicting heavy army losses in Niger.

Summit host Nigeria has also witnessed a spike in attacks in recent weeks, targeting both villagers and military bases.

In his speech, outgoing ECOWAS chair Tinubu spoke of the "stark and consistent challenges that continue to impede our aspirations... violent extremism and other cross-border crimes that have continued to widen" and intensify.

The three Sahel states' military juntas pledged during the coups that brought them to power to make security a priority.

But, like their predecessors, they are struggling to contain the advance of jihadists, who are threatening neighbouring countries on the west African coast more than ever.