The military regimes in Burkina Faso, Mali and Niger on Sunday announced their immediate withdrawal from the West African bloc ECOWAS, saying it has become a threat to member states.

The leaders of the three Sahel nations issued a statement saying it was a "sovereign decision" to leave the Economic Community of West African States "without delay".

Struggling with jihadist violence and poverty, the regimes have had tense ties with ECOWAS since coups took place in Niger last July, Burkina Faso in 2022 and Mali in 2020.

ECOWAS said in a statement on Sunday that it "remains committed to finding a negotiated solution to the political impasse" with all three countries.

It said it had yet to receive any direct formal notification of the withdrawal of the three states.

All three -- founding members of the bloc in 1975 -- were suspended from ECOWAS with Niger and Mali facing heavy sanctions as the bloc tried to push for the early return of civilian governments through elections.

The sanctions were an "irrational and unacceptable posture" at a time when the three "have decided to take their destiny in hand", the three countries said -- a reference to the coups that removed civilian administrations.

The three nations have hardened their positions in recent months and joined forces in an "Alliance of Sahel States".

The leaders' joint statement added that the 15-member ECOWAS, "under the influence of foreign powers, betraying its founding principles, has become a threat to member states and peoples".

They accused the grouping of failing to help them tackle the jihadists who swept into Mali from 2012 and then on to Burkina and Niger.

But leaving ECOWAS could make trade more difficult for the three land-locked nations, making goods more expensive, and could also see visa requirements re-imposed for travel.

Under pressure from the military regimes, former colonial power France has removed ambassadors and troops and watched Russia fill the void militarily and politically.

The French army's withdrawal from the Sahel -- the region along the Sahara desert across Africa -- has heightened concerns over the conflicts spreading southward to Gulf of Guinea states Ghana, Togo, Benin and Ivory Coast.