At least 70 migrants drowned when their boat capsized off the Tunisian coast after they left Libya hoping to reach Europe, reports suggest.

It is one of the deadliest shipwrecks involving migrants trying to reach Europe illegally this year.

The UN’s International Organisation for Migration said the sunken 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 but the state-run Tunis Afrique Presse agency gave a death toll of at least 70 people.

The boat sank 40 miles off the coast of Sfax, south of the capital Tunis, the Tunisian agency said.

Fishing boats were said to have been scrambled to rescue the survivors.

The Tunisian Defence Ministry said the boat had left from the Libyan port of Zouara yesterday, 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. (DailyMail)