More than 80 African migrants are feared to have drowned after a boat that left Libya for Europe capsized off the coast of Tunisia.
Dozens of African migrants are feared to have drowned after their boat capsized off the coast of Tunisia.
The UN refugee agency UNHCR said in a statement more than 80 were feared drowned.
Tunisian fishermen rescued four people but one later died in hospital, the UNHCR said.
"The status quo cannot continue," UNHCR Special Envoy for the Mediterranean Vincent Cochetel said in a statement on Thursday.
"Nobody puts their lives and the lives of their families at risk on these desperate boat journeys unless they feel they have no other choice.
"We need to provide people with meaningful alternatives that stop them from needing to step foot on a boat in the first place."
Some of the four initial survivors told the Tunisian coast guard on Thursday that the boat had sunk off the town of Zarzis, Red Crescent official Mongi Slim told Reuters.
A government source said some African migrants who were rescued off Zarzis told coastguards they set out from Zuwara in Libya, and that dozens had drowned.
At least 65 migrants heading for Europe from Libya drowned last May when their boat capsized off Tunisia.
Libya's west coast is the main departure point for African migrants hoping to reach Europe, though numbers have dropped due to an Italian-led effort to disrupt smuggling networks and support the Libyan coast guard.