Authorities say 17 migrants drowned and two were rescued Thursday after a boat trying to carry them to Europe sank off the Tunisian coast. The two rescued migrants were Nigerian women who narrated to their rescuers how 17 others drowned in the deep waters after they left from Libya.

It was not clear if the 17 drowned persons were all Nigerians but guards say persons from other parts of Africa and Asia often make up the contingent from Libya to Europe by sea.

Associated Press reports that a naval mission saved two women from Nigeria off the coastal town of Zarzis who said their inflatable boat had sunk with 19 people aboard, defense ministry spokesperson Mohamed Zekri told The Associated Press.

The survivors told rescuers that the boat had left from Libya on Sunday and its engine broke down at sea, he said. Zarzis is about 70 kilometers (42 miles) from the Libyan border.

Safa Msehli of the International Organization for Migration tweeted: “At least 17 migrants drowned off the Tunisian coast today according to two survivors rescued by authorities.”

The two rescued women were transported to the regional hospital in Zarzis and then taken to a quarantine zone while they await results of virus tests, said the head of the Tunisian Red Cross for the region.

It was at least the fourth deadly boat sinking in the last couple of months off Tunisian shores involving migrants escaping conflict or poor living conditions to try to reach Europe.