Germany has been a strong advocate of sanctions against Syria amid a violent crackdown by President Bashar Assad's government on the country's uprising. The 27-nation European Union has imposed an arms embargo among other measures.
German weekly Der Spiegel reported that the Atlantic Cruiser was stopped in the Mediterranean after its owners were warned it was suspected to be carrying Iranian military equipment to Tartus, Syria. Without citing sources, it said "defectors in the Syrian government apparatus" were behind the alert.
Der Spiegel quoted shipping agent Torsten Lueddeke of Hamburg-based C.E.G. Bulk Chartering as saying: "We stopped the ship after we received information on the weapons cargo."
He said the ship had been chartered to an Odessa, Ukraine-based company called White Whale Shipping and "they declared to us as cargo above all pumps and things like that," according to the report. "We would never have allowed weapons on board."
The ship's current whereabouts weren't clear. Der Spiegel - which reported that the suspect cargo was loaded in Djibouti - said it had changed course for İskenderun, Turkey, on Friday and then stopped about 50 miles (80 kilometers) southwest of Tartus and sailed in circles.
Phones at C.E.G. and W. Bockstiegel Reederei, the German owner of the ship, which flies the Antigua & Barbuda flag, rang unanswered on Saturday, and neither immediately responded to e-mailed requests for comment. C.E.G.'s website says that the company was established last year to take care of the commercial operations of Bockstiegel's bulk carriers.
The Ukrainian company also could not be reached for comment.