Tunisia is just a few hundred kilometres (miles) from mainland Europe, and has long been a launchpad for illegal migration to the continent.
Tunisia’s coastguard on Thursday retrieved the bodies of 20 migrants from sub-Saharan Africa after their boat capsized at sea, a spokesman for the defence ministry said.
Five other migrants who were on board were rescued, ministry spokesman Mohamed Zekri told AFP, adding that a search operation was underway.
Zekri did not give further details, but said the rescue operation took place off the port of Sfax in central Tunisia.
Khaled Hayouni, a spokesman for the interior ministry, said the boat was heading to Italy from the Sidi Mansour district of Sfax when it sank.
More than 40 people were on board the makeshift boat, Mourad Turki, a spokesman for the Sfax court, told AFP.
He said that some of the 20 bodies recovered were taken to a Sfax hospital for an autopsy to determine the cause of death.
Departures by desperate migrants seeking a new life in Europe peaked in 2011, following the revolution that overthrew Tunisian dictator Zine El Abidine Ben Ali.
Although numbers have dropped significantly in recent years, illegal crossings from Tunisia to Europe jumped by more than 150 percent in January to April compared to the same period last year, according to the UN refugee agency.
Many of the migrants are from sub-Saharan African countries fleeing economic hardship and crisis at home.
According to the interior ministry, 8,581 migrants were intercepted after setting off on the perilous Mediterranean crossing between.