The migrants, aged between 15 and 40 and almost all men, left from neighbouring Libya late Thursday.

But their boat began to founder in waters off the southern Tunisian port of Ben Guerdane, the defence ministry said in a statement.

The migrants -- who include citizens of multiple nationalities, many from sub-Saharan African countries -- were taken to Ben Guerdane, before heading to a detention centre.

Tunisia and Libya are key departure points for migrants attempting the dangerous crossing from the North African coast to Europe, particularly Italy.

At least 700 people have died trying to cross the central Mediterranean this year, up until May 17, the UN's refugee agency UNHCR said.

Numbers leaving Libya have also increased significantly, with 11,000 departures from January to April 2021, over 70 percent more than in the same period last year, according to UNHCR.