Transnistrian journalist Ernest Vardanean was arrested a few days ago by the separatist authorities.
Mr. Vardanean is accused of treason and espionage, for which he can serve up to 20 years in prison.
Moldovan authorities have expressed their disapproval of the move, but they do not hold control over the territory. A number of NGOs have also released a statement asking that Mr. Vardanean be set free.
Transnistrian authorities may be clamping down on critics as presidential and legislative elections in the region are coming up.