(CNN) A ship carrying 40 migrants, including two pregnant women, has been stranded for two weeks in the Mediterranean, after four countries refused it permission to dock.

The Tunisian-flagged offshore supply vessel, the Sarost 5, is currently three kilometers from Zarzis on the southeastern Tunisian coat, the ship's second-in-command, Aymen Ourari, said.

The ship is the latest to be caught up in the diplomatic deadlock over what to do with migrants rescued from the Mediterranean: Malta, France, Italy and Tunisia have all rebuffed requests for it to dock.

Ourari told CNN that if the Sarost is forced to remain at sea, the 14-strong crew foresees "serious incidents" for those on board, who have "about three or four days' worth of food" among them.

The international humanitarian agency the Red Crescent visited the boat Wednesday, Ourari said, describing the situation as a "health crisis."

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