Strategy Page raises the issue of the use of Syrian merchant hulls as possible delivery vehicles for the Iranians here:
Syrian involvement in seaborne smuggling is one of the reasons it got tagged as part of the Axis of Evil. Get Syria out of the terrorism business, and you might get them out of the smuggling business as well. But that's unlikely. The Syrian government needs the money. Iran was generous with its "foreign aid" because Syria provided support for terrorists Iran backed. Now Iran is keen on getting nuclear weapons. The first ones Iran will get will be large and delicate. The only feasible intercontinental delivery system will be a ship. A ship that is accustomed to moving illicit goods.Earlier reports of Iran experimenting with missiles on merchant ships here and here. Strategy Page names names of the suspect shipping companies.