The Tunisian coastguard said on Thursday it recovered the bodies of 13 sub-Saharan African migrants and rescued 25 after their boat sank en route for Italy.
The tragedy occurred off the city of Sfax, the coastguard said, without saying how far off shore the boat was when it sank.
Tunisia is facing an unprecedented migration crisis, having replaced Libya as the region's main departure point for people fleeing poverty and conflict in Africa and the Middle East in the hope of a better life in Europe.
The number of dead and missing off the North African country's coasts rose to around 630 in the first half of 2023, far more than in any previous year, according to figures compiled by Reuters.
Tunisia is under pressure from European countries to stop large numbers of people departing from its coasts, but President Kais Saied has said it will not act as a border guard.