Detectives from the PSNI’s Serious Crime Branch detained the 49-year-old yesterday morning in Strabane.
The arrest came as part of investigations into “ongoing violent dissident republican activity” in the town.
The PSNI said the man has been released pending a report to the Public Prosecution Service.
Numerous searches have been carried out in the area since a mortar bomb and a rifle was uncovered in the town last month.
Local Councillor Patsy Kelly says police must be looking for something else: