Gov. Babajide Sanwo-Olu has given the traders under the Apongbon Bridge in Lagos Island three days to vacate the place.
The governor said any structure found under the bridge on Wednesday will be demolished.
Sanwo-Olu gave the warning while driving on the bridge, during the inspection of the blue line rail project.
He saw that traders were back under the bridge with their goods displayed after they were driven away in the aftermath of the fire that occurred four weeks ago.
The governor frowned at the unlawful return of the traders.
He said the enforcement team would be deployed to the bridge on the expiration of the ultimatum.