As many as 40 migrants drowned off the coast of Libya earlier this week, according to humanitarian organisations citing witnesses on Friday.
At least 88 sub-Saharan migrants were disembarked on Thursday by German navy vessel Holstein in the Sicilian port of Augusta, and spoke to volunteers from the UN agency for refugees, the UNHCR, the International Organisation for Migration and the Save the Children charity.
"We heard from them that 35 to 40 people died," Giovanna Di Benedetto, a spokesperson for Save the Children, told dpa.
She said the migrants came from countries such as Senegal, Mali, Benin and Nigeria.
They said their dinghy started taking in water on Wednesday morning, sometime after setting off for Libya. Amid scenes of panic, people fell in the water. Some more fell during rescue operations, carried out by a merchant ship which later transferred the migrants to the German navy boat.
"What happened exactly is not clear," Di Benedetto said.
Federico Fossi, a spokesperson for UNHCR, said his organisation was treating the reports with "caution", since there were some discrepancies in what traumatised survivors told volunteers. But he confirmed the presumed 35-40 death toll.
A spokesperson for the Italian coast guard said he could not confirm nor deny the deaths, but noted that no bodies had been found.