A boat carrying more than 70 migrants capsized off the coast of Tunisia after setting off for Europe from Libya, a government source and the Tunisian Red Crescent said.
Some of the four initial survivors told the Tunisian coast guard on Thursday that the boat had sunk off the town of Zarzis yesterday, Red Crescent official Mongi Slim said.
One of the four died later in hospital, Slim said, adding that no more information was available.
A government source said that some of a group of African migrants who were rescued nine miles off the town of Zarzis had informed coastguards that they had set out set out from Zuwara in Libya, and that dozens had drowned.
At least 65 migrants drowned last May when their boat capsized off the Tunisian coast after they had left Libya hoping to reach Europe.
Libya's west coast is a main departure point for African migrants hoping to reach Europe with the help of human traffickers.
However, numbers have dropped due to an Italian-led effort to disrupt smuggling networks and support the Libyan coast guard.
Although the fighting in Libya has made the situation more difficult for people-trafficking, international aid officials have warned that it could also prompt more Libyans to flee their country.
This story is being updated
