The bodies of 25 migrants who tried to reach Europe have washed up on Tunisia's coast in the past few days, the International Organization for Migration said Monday.
They were recovered on the beaches of Nabeul, 70 kilometres (45 miles) south of Tunis between Friday and Saturday, a statement said.
Saturday, the Tunisian civil defence gave a lower toll, saying 17 bodies had been found off Cape Bon, a peninsula on the strait of Sicily.
"The boat they were on likely left Tunisia several days ago with around 60 people on board," the IOM said.
"Efforts to identify them are under way but according to the information available, they were Syrian and Tunisian migrants."
Tunisia and neighbouring Libya are major conduits for migrants, particularly from African countries ravaged by war and poverty, to make desperate bids to reach Europe.
Many end up drowning in the attempt, making the central Mediterranean the world's deadliest migration route.
The IOM said it was "deeply concerned by the loss of human life resulting from a growing number" of similar accidents this winter.
In an open letter on Monday, 37 rights groups called on Tunisian authorities to "take effective and practical steps to save the lives of migrants in Tunisian territorial waters".
One signatory, the Tunisian Forum for Economic and Social Rights (FTDES), had said earlier this month that more than 15,600 migrants had managed to reach Italy from the Tunisian coast in 2021, up by more than a fifth from the previous year.
Around 2,000 migrants were missing or confirmed drowned in the Mediterranean last year, up from 1,401 in 2020, according to the IOM.