CID spokesman Chris Grey said that the investigation into the theft earlier this month at Panzer Kaserne, part of US Army Garrison Stuttgart, is still ongoing.
"Several semi-automatic pistols, one small-caliber automatic rifle and a shotgun were among the items taken," from an armory room on the base in Stuttgart, he said.
"At this point in the investigation it does not appear that an outside entity stole the firearms and equipment or breached the fence line, but we have not completely ruled it out," Grey said.
At least ten Germans have been killed and dozens more injured in four attacks in Wurzburg, Munich, Reutlingen and Ansbach, three of which have been linked to Islamic terrorism.
In July last year French authorities were similarly alarmed after the theft of up to 190 detonators, a stock of plastic explosives and around 40 grenades from a base in southern France. The theft occurred despite the country being on high terror alert since the Charlie Hebdo attacks in January 2015.