Forty-three people died while 80 people survived when a boat carrying migrants crashed against rocks near the coast of southern Italy early on Sunday, the Italian coast guard and police said.
The shipwreck took place near Steccato di Cutro, a seaside resort on the eastern coast of Calabria, the region that forms the tip of Italy's boot.
"At present, a total of 80 people have been found alive - some of whom have managed to reach the shore after the shipwreck - and 43 bodies have been found along the coast," the coast guard said in a statement.
The boat was carrying about 120 people and hit rocks "a few metres from the shore," the coast guard said, adding that the search for other possible survivors was still on.
Earlier, the Mayor of Cutro, Antonio Ceraso, told the SkyTG24 news channel that women and children were among the dead.
He said the migrants' wooden boat had "disintegrated" amid stormy sea conditions, with parts of the wreckage ruins strewn across some 300 metres of the coast.
His voice cracking up, Ceraso said he witnessed "a spectacle that you would never want to see in your life ... a gruesome sight ... that stays with you for all your life."
Firefighters were searching the sea on jet skis, but conditions were harsh making the operation difficult, Calabria firefighters' spokesman Danilo Maida told Reuters.
Initial reports from ANSA and other Italian news agencies, spoke of 27 bodies washed up on the beach and more found in the water.
Italian news agency Adnkronos said the migrants caught up in the shipwreck came from Iran, Pakistan and Afghanistan, while ANSA said they came from Iran, Iraq, Afghanistan and Syria.
Italian Prime Minister Giorgia Meloni expressed "deep sorrow" for the deadly incident, and vowed to stop irregular sea migration to prevent more deaths at sea.
Her right-wing government has taken a hard line on migration since it took power in October, mostly by restricting the activities of migrant rescue charities with tough new laws.
"It is a huge tragedy which shows the absolute need to act firmly against irregular migration channels," Interior Minister Matteo Piantedosi said in a separate statement.
It was "essential" to stop sea crossings which, offering migrants the "illusory mirage of a better life" in Europe, enrich traffickers and "cause tragedies like today's", he added.
Italy is one of the main landing points for migrants trying to enter Europe by sea. The so-called central Mediterranean route is known as one of the world's most dangerous.
According to the International Organisation for Migration's Missing Migrants Project, 20,333 people have died or gone missing in the central Mediterranean since 2014.