The Afghan government has ordered the closure of all offices of a group that wants to promote new ways of dealing with the global drugs problem.
Poppies grow in most Afghan provinces
The Interior Ministry said the Senlis Council, had been "confusing farmers" and had been a factor in the increase in poppy cultivation.
Senlis has suggested the legal use of Afghan opium for medical purposes.
A spokesman for Senlis said it had not received any formal notification that its offices were to be closed.
He denied its activities had increased poppy cultivation.
Correspondents say there has been tension over a recent council report blaming the government for a failure to stop farmers growing poppies.
Afghanistan is building a new counter-narcotics police force but reports say the force only has personnel in nine of 34 provinces.
Only six provinces are reported to be opium-free.