Leaders from 44 African countries have signed an agreement to form a $2.5 trillion continental free-trade zone.
Nigeria and South Africa, the continent’s largest economies, were however absent.
Deliberations on the free-trade zone began in 2015 and was originally projected to capture 55 countries.
At the African Union summit in Kigali, Rwanda, Paul Kagame, host president, declared the meeting a success after initial negotiations were concluded.
President Muhammadu Buhari had been initially scheduled to attend the summit and sign the agreement after the federal executive council gave its approval at its March 14 meeting.
The trip was cancelled on Sunday, March 18 and the presidency did not give a reason for the development.
On his part, South African President Cyril Ramaphosa, said his country will join the agreement when the necessary legal processes are concluded.