The heads of state and government from most of the EU member countries and more than 30 African nations are due in the Maltese capital Valletta on Wednesday for talks on tackling Europe's migration crisis.

The two-day summit ending Thursday will be followed immediately by an informal gathering of EU leaders who will take stock of their quest for a unified response to the continent's biggest movement of people since World War II.

Rival protests featuring those welcoming migrants and far-right wingers opposed to their presence were held in the British port town at the mouth of the Channel Tunnel on Saturday.

Small groups gathered in Folkestone, southeast England, with.around 20 people in support of the migrants, while about 30 others turned out to protest against immigration. 

EU foreign ministers formally approved Monday the launch of the first phase of a military operation to target people smugglers in the Mediterranean, officials said.

The initial ships and aircraft to conduct intelligence gathering missions should be available within a week, officials said.

A total of 741 migrants who set sail from Libya in the hopes of reaching Europe were rescued in the Mediterranean on Thursday, the Italian coastguard said.

The rescue operation was coordinated by the coastguard, a spokesman told Agence France Presse, and carried out with the help of German, Irish and British naval vessels under the auspices of the EU's Frontex border control agency. 

Austrian Chancellor Werner Faymann on Monday called for an EU-wide quota to help accommodate the thousands of refugees reaching Europe's southern shores by boat and prevent further deaths.

He said the influx of migrants should not be borne alone by the countries where they first arrive -- Italy and Malta -- but equally distributed across EU member states.

Italy's coastguard attempted to rescue more migrants in the Mediterranean Sunday after nearly 3,700 were picked up trying to reach Europe on Saturday alone.

Although it was not a record, the number saved was one of the highest ever recorded in a single day, and raised fears that the tide of desperate people trying to reach Europe has not been slowed by recent disasters.

Up to 700 people were feared drowned Sunday after an overcrowded boat smuggling them to Europe capsized off Libya in the latest and deadliest in a long list of migrant disasters in the Mediterranean.

Italy's coastguard, which was coordinating the search for survivors and bodies, said only 28 people had survived a wreck that triggered fresh calls from Pope Francis and others for European leaders to act over what many saw as an avoidable tragedy.

More than 3,000 migrants have died trying to cross the Mediterranean so far this year, more than double the previous peak in 2011, the International Organization for Migration said Monday.

Europe is by far the most dangerous destination for "irregular" migrants, the organization found in a report, with 3,072, or 75 percent, of the 4,077 registered migrant deaths worldwide since January happening in the Mediterranean.

Police have arrested a Lebanese smuggler and scores of Syrians and Palestinians trying to flee to Italy, the state-run National News Agency reported on Wednesday.

Around 107 Syrians and Palestinians from the southern refugee camp of Ain el-Hilweh were arrested at the port of the northern city of Tripoli, NNA said.

People smugglers who allegedly sank a boat killing up to 500 migrants are likely guilty of "mass murder" and should be brought to justice, the U.N.'s new rights chief said on Friday.

"The callous act of deliberately ramming a boat full of hundreds of defenseless people is a crime that must not go unpunished," Zeid Ra'ad Zeid al-Hussein said in a statement.