The chief of the German Navy recently confirmed that a number of the service's vessels have been sabotaged.
In a recent press conference, Inspector of the Navy Vice Admiral Jan Christian Kaack said "more than one unit" was targeted. However, he did not disclose the exact number of affected ships.
Kaack added that there had also been attempts to break into naval bases as well as attempts by various individuals to approach uniformed navy personnel in public.
One recent incident of suspected sabotage was the placement of an undetermined quantity of metal shavings into the engines of a warship still under construction at a yard in Hamburg.
Local news outlets have identified the warship as the Braunschweig-class corvette Emden, which is scheduled to be handed over to the navy later this year for deployment to the Baltic Sea.
Local media said that if the shavings had not been detected, these would have resulted in significant damage to the ship's propulsion machinery.
Kaack, however, did not directly confirm whether Emden was among the affected ships.