Counter terrorism officers have arrested a 22-year-old man in Glenrothes.
The action by the Police Scotland officers on Saturday follows an intelligence-led operation in the town.
It is thought the man may have been preparing an act of terrorism.
Police have stressed there is nothing to suggest any further threat.
In a statement, Police Scotland said the man was arrested “on suspicion of engaging in conduct in preparation for committing acts of terrorism” contrary to section five of the Terrorism Act 2006.
He is being held in police custody and enquiries are continuing.
Detective Chief Superintendent Phil Chapman said: “Our enquiries are ongoing in the Glenrothes area but I would like to reassure the public that there is no intelligence to suggest there is any further threat.”