The investigation is led by prosecutor Carl Mellberg at the National Security Unit.
"I can only confirm that a preliminary investigation is underway regarding preparation for a terrorist crime and participation in a terrorist organization, both serious crimes. One person has been arrested," he tells TT.
The investigation is being conducted by the Security Service, which confirms that the arrest was made on Friday, but does not want to comment further on the matter. Interrogations are expected to be held this weekend.
The man's lawyer tells TT that she has no comments at this time.
