The Italian navy says 34 bodies have been recovered and 206 people rescued after a vessel smuggling immigrants from North Africa overturned in the Channel of Sicily.
Local media, quoting sources among the rescuers, reported that the death toll could be as high as 50, with 10 children among the dead.
A rescue ship has been dispatched to help another boat in distress in the area, the Italian navy said on Saturday.
Friday’s incident took place about 60 miles south of the island of Lampedusa, in Maltese waters.
The Italian coast guard received a satellite phone call from the boat that was in distress and was able to locate it based on the satellite coordinates, said coast guard spokesman Marco Di Milla.
A Maltese aircraft was sent up and reported that the boat had capsized and that “numerous” people were in the water. The aircraft dropped a life raft, and a patrol boat soon arrived at the scene.
The Maltese Navy said it appeared that the boat had capsized when the migrants on boat started moving to attract attention.
Helicopters airlifted injured people to Lampedusa. The tiny island is 70 miles from Tunisia, closer to Africa than the Italian mainland, and is the destination of choice for most boats leaving Tunisia or Libya.
The latest incident comes just eight days after another disaster off Lampedusa in which as many as 363 people, mostly of Eritrean and Somali origin, may have died. The body of a newborn baby was recovered with the umbilical cord still attached.
Joseph Muscat, the Maltese prime minister, said the people on board the boat that capsized on Friday were fleeing the conflict in Syria.
Mr Muscat said the island is struggling to cope with the burden of patrolling a stretch of the Mediterranean where waves of refugees and economic migrants continue to take their chances.
He told Sky News: “The difference from last week’s tragedy is that these people, instead of Somalia, they hail from Syria which makes the case even more complicated and shows the immense humanitarian tragedy that the Mediterranean is experiencing right now.
“Our forces, the Italian forces, are not guarding Maltese or Italian boarders. We are guarding European borders but we are left on our own. We feel totally abandoned and isolated by Europe and that’s what myself and the Italian prime minister have agreed to tell the European Council later this month.”
He added: “The fact is that these people don’t want to come to Malta. They want to come to Europe.
“That’s something that maybe Brussels is not realising to the full. So right now we have stamped our feet in the past, saying look guys, don’t leave us on our own. We will comply to international regulations, we will save lives as we did last night but this can’t go on.”
During a visit to Lampedusa this week, European Commission President Jose Manuel Barroso has promised Italy 30 million euros in EU funds to better care for newly arrived migrants.
Fortress Europe, an Italian observatory that tracks migrant deaths, says about 6,450 people died in the Channel of Sicily between 1994 and 2012.
Despite the dangers of the sea voyage, would-be immigrants are still prepared to pay more than 1,000 euros each for the hope of a better life in Europe.
Some 30,100 migrants arrived in Italy and Malta in the first nine months of 2013, compared with 15,000 in all of 2012, according to the UN refugee agency.
Once in Italy, migrants are screened for asylum and often sent back to Africa if they don’t qualify.