Brad Pitt‘s epic zombie thriller has run into trouble with Hungarian authorities after an anti-terrorism squad raided a warehouse holding guns to be used during the filming. The only problem was that the guns, which were supposed to be non-functional, were in perfect working order.

Us Weekly reports that 85 fully-functional automatic and military-style assault rifles were confiscated at an airport near the film’s Budapest set, where they were being stored.

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Hajdu Janos and Zsolt Bodnar, the director and deputy director of Hungary’s Anti-Terrorism Unit stated, “This morning a private plane brought guns wrapped in a parcel from a company to an individual [in Budapest]. Guns like these are highly illegal to transport even if they were used as stage guns, which hopefully they weren’t.”

The authorities say they are interrogating witnesses now.

The film, directed by Oscar nominee Marc Forster, has been shooting in Hungary after filming in Glasgow during August and September.

Pitt stars as a UN Employee traveling the world to try and stop a zombie plague from decimating humanity. The film is due out from Paramount Pictures in 2012.