Italy and Malta called for EU action, after 34 migrants died after their boat capsized and sank off the island of Sicily on Friday.
Some 30,100 migrants arrived by sea to Italy this year, the UN says.
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Italian and Maltese naval vessels have recovered 34 bodies from a migrant boat that capsized in the Mediterranean, the Italian navy has said.
Italian media said that the boat capsized on Friday when panicked people aboard waved for help.
The Italian navy added that a rescue ship had been dispatched to help another boat in distress in the area.
The recent deaths prompted renewed calls for the European Union to do more to better patrol the southern Mediterranean and prevent tragedies - and for countries like Libya to crack down on smuggling operations.
"We cannot allow the Mediterranean to become a cemetery," Malta's prime minister Joseph Muscat said.
Lampedusa is the destination of choice for smugglers who usually charge more than 1,000 euro (£850) a head and cram the migrants onto boats that routinely run into trouble and require rescue.
Fortress Europe, an Italian observatory that tracks migrant deaths reported by the media, says about 6,450 people died in the Canal of Sicily between 1994 and 2012.
Malta's prime minister says 27 people are confirmed dead after the capsizing of a migrant ship off the Sicilian island of Lampedusa.
Joseph Muscat said over 200 people have been rescued and that the search is continuing.
He said at least three of the 27 dead are children.
Some 206 survivors have been recovered from the sea following the capsizing of a boat near Italy, according to the Armed Forces of Malta.
In a post on its Facebook page, the AFM said it was confirmed that 180 adults and 26 children had been rescued by itself and the Italian Navy.
The page also reports that "at least 4 deceased persons have also been recovered".
Around 50 corpses have so far been sighted where a boat carrying African migrants capsized near Italy, including around 10 children.
The news was reported by Italian news agency ANSA, after the boat spilled around 250 passengers into the sea between Sicily and Tunisia.
Many of the migrants aboard a boat that capsized off Lampedusa have survived, according to Italy's coast guard.
Spokesman Marco Di Milla says "a good number" of the estimated 200 people have been rescued.
He says the coast guard was able to locate it based on the coordinates of a satellite phone call it made.
Helicopters are reportedly taking the injured to the Sicilian island.
Italian broadcaster RAI has shown footage purporting to show the rescue operation underway off the coast of Sicily.
What appears to be the hull of a boat is visible under the green and red vessel.
A migrant boat that capsized near the coast of Sicily had around 250 people on board, according to the Italian news agency ANSA.
It also reports that two Navy vessels are in the area and that helicopters and inflatable boats are also helping with the rescue effort.
Italy's Navy has said that another migrant broat has capsized off the coast of Sicily.
At least 200 people are in the sea and Navy vessels are assisting in the rescue operation.
Earlier this month a migrant boat sunk off Italy, killing 232 people.
Authorities say a further 38 bodies have been recovered following the Lampedusa boat tragedy, taking the death toll to 232. Scores more are believed missing; most, if not all, were Eritreans trying to reach Europe in search of asylum and a better life.
"They unpacked a wall of people," said Navy Capt. Paolo Trucco of the deep sea specialists. The bodies "were so entwined, one with the other, it is indescribable. They were so trapped they were difficult to pull out."
Deep sea divers in their weighted suits and sturdy port-holed helmets were able to spend up to 30 minutes at a time at the site of the wreck 47 metres below the surface.