At least 50 migrants drowned when their boat capsized in the Mediterranean Sea off the Tunisian coast after they had left Libya hoping to reach Europe, the United Nations migration agency says.
The state-run Tunis Afrique Presse agency gave a death toll of at least 70 people.
It was one of the deadliest shipwrecks involving migrants trying to reach Europe illegally this year.
The UN's International Organisation for Migration said on Friday the boat took to the sea from neighbouring Libya, where renewed warfare between rival factions has gripped the capital Tripoli in the past five weeks. It put the number of victims at 50, with 16 survivors.
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The boat sank 64km off the coast of Sfax, south of the capital Tunis, the Tunisian agency said. Fishing boats rescued the survivors.
The Tunisian Defence Ministry said the boat had left from the Libyan port of Zouara on Thursday aiming to reach Italy. Navy units have recovered only three bodies so far, it said in a statement.
"Another tragedy in the Mediterranean," the IOM said.
Libya's western coast is a main departure point for migrants from across Africa hoping to reach Europe by paying human traffickers, though numbers have dropped due to an Italian-led effort to disrupt smuggling networks and support the Libyan coast guard.
Italy's Interior Minister Matteo Salvini let a charity boat carrying 30 rescued migrants dock at an Italian port but said the vessel would be impounded and not let out to sea again.
The migrants, including two pregnant women, a baby and four unaccompanied minors, were picked up by the Mare Jonio on Thursday off the coast of Libya as their rubber boat was sinking.
Earlier on Friday, UNHCR spokesman Babar Baloch said the United Nations had repeatedly voiced its concerns about the lack of boats to pick up migrants and refugees fleeing from "the horrendous and horrible situation" in Libya. It called on governments to step in.