The ship had set sail from Turkey bound for Libya, with a declared cargo of plastics. It was stopped and searched by a coast guard special forces team off Ierapetra, as part of a wide-scale operation.
There is a seven-member crew made up of Syrians, Egyptians and Indians.
Special security measures have been taken at Heraklion port, where a full-scale search of the ship will be conducted, and customs officers had been summoned to assist.
