Karin Rosander at the prosecutor service says the two men are suspected on probable cause of breaking laws that protect key infrastructure. The two men are believed to have gone to Muskö several times before they were caught. They could get two years in prison.
The two men say that they are tourists and very interested in military bunkers. They were detected within the naval base's perimeter on Sunday night, and had gone past a fence and warning signs. The sentry fired warning shots when they were discovered.
Swedish Radio News has investigated the British suspect and his online activity seems to confirm that he has long been interested in military bunkers.
Much of the Muskö base is built into solid rock. It is currently being expanded to host the naval headquarters.