At least seven trucks loaded with redwood timber were impounded by the ECOMIG stabilization force in the southern Gambian city of Bwiam.
The truck drivers say West African authorities, mostly Senegalese troops told them they had received orders to seize any truck suspected of transporting illegal timber.
The timber from some of the trucks has been uploaded and stashed as evidence at a military camp in Bwiam, about 65 miles southeast of the capital, Banjul.
The truck drivers say they have documentation giving them permission to transport the timber. Most of the timber is suspected to be from the southern Senegalese region of Casamance.
Gambian authorities had put a ban on the exportation of redwood timber in January. The ban remains in places but an exception was given for the exportation of timber that was already set for export.
However, timber could be imported but customs duties and clearances have to be paid and issued, according to Mr. Ousainou Cham, the Principal Forestry Officer for the West Coast Region.
Importers have to also show proper documentation to prove that the timber and vendor certificate was legally acquired. It is suspected most of the timber from exported from The Gambia are illegally acquired from Casamance.
Many timber exporters were unable to ship their timber before the July 31 deadline because of logistical constraints, especially at the Gambia Ports Authority.
The seaport was overwhelmed at the time, which was the height of the cashew season when the small country sees a high export of cashew nuts.
Gambian authorities have checked the information of the impounded vehicles and said they have legally acquired their timber. They have contacted the ECOMIG force to release the vehicles.
It is the second large impound of vehicles reported in seven months. Nearly a dozen vehicles were impounded in February in the aftermath of the political standoff that brought the West African troops to secure the country.