A photograph released by the Hellenic Coast Guard shows boxes of ammunition that were found on the Libya-bound ship.
An inventory of unregistered weapons found on the Bolivian-flagged Haddad 1, a Libya-bound freighter that a coast guard special unit stopped off the island of Crete earlier this week, includes 4,881 police-type shotguns, suitable for urban warfare, and 491,950 9 mm rounds of ammunition, Greek authorities said on Thursday.
Officials said most of the containers also contained an unspecified number of contraband cigarette packs.
The seven crew members are expected to face a prosecutor Friday.
The Haddad 1 sailed from the Turkish port of Iskenderun on August 29 and was headed for the rebel-held port of Misrata in Libya – currently under a UN arms embargo.