Around 40 migrants are said to have drowned off the coast of southern Italy while attempting to cross the Mediterranean, Save the Children said on Tuesday, citing interviews with survivors of the shipwreck.
"Survivors told us that [about 40] migrants fell into the water," charity spokeswoman Giovanna Di Benedetto told Germany's DPA news agency from the eastern Sicilian port city of Catania, where nearly 200 migrants arrived after being rescued by Italian coastguard.
Details of the circumstances surrounding the recent tragedy have yet to be released.
The United Nations refugee agency fears over 1,750 people have already lost their lives in the Mediterranean this year - 30 times more than in the same period of 2014 - amid an unrelenting surge in migrant crossings.
If the migrant crisis continues unabated, there could be 30,000 deaths at sea this year and Italy will have to handle 200,000 would be asylum-seekers landing on its soil, aid groups predict.
Charities, the United Nations and the European Parliament have urged the EU executive to expand its limited Triton border patrol mission to include search and rescue operations in the Mediterranean.
One out of every 23 migrants who set sail from North Africa between January and March perished on the journey, an April report from Amnesty International showed.
The issue gained new urgency on 19 April, when up to 950 people are believed to have died in a shipwreck 80 nautical miles north of Libya.
EU leaders subsequently tripled funding for Trident and agreed to go after the people smugglers organising the treacherous boat migrant boat journeys.