The 15-nation West African bloc ECOWAS told regional leaders Tuesday that the goal of establishing a single currency among their economies in 2020 had failed.
"The roadmap has not been implemented vigorously," Marcel de Souza, president of the ECOWAS Commission, told a summit in Niamey, the capital of Niger.
"We cannot move to the single currency in 2020," he said.
Four goals had been set down for introducing a single currency but "there are not the results to match," de Souza said.
"From 2012 to 2016, none of our countries has been able to persistently uphold the prime criteria in the programme for macro-economic convergence," he said.
The summit aims at assessing progress towards a single regional currency 30 years after the goal was first sketched.
ECOWAS -- the Economic Community of West African States -- was set up in 1975.
Today it comprises Benin, Burkina Faso, Cape Verde, Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, Niger, Nigeria, Senegal, Sierra Leone and Togo, which together have 300 million inhabitants.
Tuesday's announcement came after a string of revisions and postponements to the monetary integration plan over the years.
In 2013, ECOWAS tasked Niger and Ghana with "coordinating" the single-currency campaign, and in 2014, a "task force" was set up to provide them with guidance.
But De Souza listed a number of setbacks, including failures to harmonise monetary policies between the eight currencies used by ECOWAS economies, and to set up a "monetary institute" -- a forerunner of a common central bank.
Eight ECOWAS countries (Benin, Burkina Faso, Guinea-Bissau, Ivory Coast, Mali, Niger, Senegal and Togo) jointly use the CFA franc.
They are moored to the single European currency and are gathered in an organisation called the West African Monetary Union, or WAMU.
But the seven other ECOWAS countries have their own currencies, none of them freely convertible amongst themselves.
Presidents Mahamadou Isoufou of Niger, Alassane Ouattara of Ivory Coast, Nana Akufo Ado of Ghana, Muhammadu Buhari of Nigeria and Faure Gnassingbe of Togo took part in the summit.