Dutch police arrested an 18-year-old man suspected of distributing propaganda for the Islamic State militant group, the national prosecutors office said on Wednesday.
The suspect was detained last Thursday in the central city of Utrecht on suspicion of spreading violent videos and possibly instructing others on how to make explosives.
A judge ruled Tuesday that the man would be held in custody for at least two weeks pending further investigations, a prosecution statement said. He has not yet been charged with any offences.
Dutch security services believe an attack in the Netherlands is likely. The country's threat assessment level has been at four out of five since March 2013.
Dozens of Dutch youths have joined Islamic State fighters in the Middle East in recent years and authorities are concerned they could carry out attacks when returning home.