The Coast Guard rescued five people and searched for another 20 people who were not yet identified, the official said.
“The boat sank about six miles off the coast of Sfax. Twenty bodies were recovered, another five were rescued and all came from sub-Saharan Africa,” said security official Ali Ayari.
About 45 people were on the boat when it sank, he added.
The coastline near the Tunisian port city of Sfax has become a major starting point for people fleeing conflict and poverty in Africa and the Middle East and seeking a better life in Europe.
Countries, including Italy and Malta, have seen an increase in arrivals at sea this year from Tunisia – where high unemployment and uncertain socio-economic conditions have driven migration – and Libya, where conflict and war have been a major factor, according to the United Nations. United Nations High Commissioner for Refugees (UNHCR).
Thursday’s deaths add to the already long list this year, even with Covid-19 travel restrictions.
According to the IOM, the boat carried more than 120 people, including women and children.
Soda called for a change in “the unfeasible approach of Libya and the Mediterranean, including the cessation of returns to the country and the establishment of a clear landing mechanism followed by solidarity from other states.”
“Thousands of vulnerable people continue to pay the price for inaction both at sea and on land,” he said.
Migration-related deaths are often under-reported and unrecorded, according to the IOM, which also said the pandemic made it more difficult to collect such data.
Emma Reynolds of CNN and Sharon Braithwaite contributed to this report.