The person - who was arrested on Monday - is suspected of preparation for a terrorist crime, serious participation in a terrorist organization and public incitement to terrorism.
"It is a case we have been working on for some time," says Jonathan Svensson, press spokesperson for the Swedish Security Service.
The investigation is being led by Säpo. Details of what happened are scarce.
"The case has no connection to any other ongoing case. The preliminary investigation continues and we will question the suspect and conduct a search of the house," says Svensson.
Corrected version: In a previous version there was incorrect information about the suspect's gender.
