Migrants seeking a better life in Europe have died by the thousands in the Mediterranean Sea in recent years while fleeing poverty and bloodshed in Africa, the Middle East and Asia.

The precise number of deaths is unknown. Authorities count only those bodies found in the sea, on shore, or aboard boats. Survivors often tell of fellow passengers who lost their lives at sea, but the bodies are never found.

As many as 1,500 migrants are believed to have died trying to cross the Mediterranean so far this year. Many were children.

The death toll in 2015 is on course to far exceed the 3,200 people who died making the journey in 2014 – according to the International Organisation for Migration – given that the summer peak has not yet begun. Fewer than 100 of the deaths in 2014 took place before May.

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April 20, 2015: Migrants are rescued by members of the Greek Coast guard and locals after a wooden sailboat carrying dozens of immigrants ran aground off the coast of the island of RhodesArgiris Mantikos/Eurokinissi/Reuters
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April 19, 2015: A child is carried off a boat by a rescue worker at the Sicilian port of Pozzallo. Some 98 migrants were rescued from rickety craft bobbing in the MediterraneanAlessandro Bianchi/Reuters
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November 5, 2014: Two people rest at Maspalomas beach on Gran Canaria after travelling from Africa in a fishing boatBorja Suarez/Reuters
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October 4, 2014: A rubber dinghy with 104 people on board waiting to be rescued is seen some 25 miles off the Libyan coastDarrin Zammit Lupi/Reuters
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August 23, 2014: Members of Libya's coast guard recover the body of a migrant off the coast of Tripoli. A wooden boat carrying up to 200 migrants sank just one kilometre off the Libyan coast, with most passengers feared drownedReuters

Migrants pay thousands of dollars to human traffickers in Libya and other refugee transit hot spots for the perilous voyage across the Mediterranean.

Libya's plunge into anarchy has created an ideal environment for smugglers, who pack people fleeing war and poverty in the Arab world and sub-Saharan African onto rickety boats that set sail for Europe -- mainly aiming for Italy or Malta.

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August 12, 2014: A rescued woman and her baby disembark from a Spanish coast guard vessel in TarifaMarcos Moreno/AFP
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June 1, 2014: Hundreds of migrants are seen aboard an Italian Navy vessel before disembarking in the Sicilian port of AugustaAntonio Parinello/Reuters
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May 14, 2014: Around 250 migrants are hoisted onto a landing craft of an Italian Navy ship after being rescued in the Mediterranean between Italy and LibyaGiorgio Perottino/Reuters
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October 4, 2013: A boat is seen under water after it sank off the southern Italian island of Lampedusa. The Italian coast guard rescued 155 people, but it is thought more than 360 drownedVigili del Fuoco/Reuters
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October 5, 2013: Coffins are laid out in a hangar at Lampedusa airport after a boat packed with migrants sank, killing more than 360 peopleAlberto Pizzoli/AFP

European officials are struggling to come up with a policy to respond more humanely to an exodus of migrants travelling by sea from Africa and Asia to Europe, without worsening the crisis by encouraging more to leave.

An Italian naval operation in the southern Mediterranean, known as "Mare Nostrum", was cancelled in 2014, partly because of its cost, but also due to domestic opposition to sea rescues that could encourage more migration.

It was replaced in November 2014 by a far smaller EU mission with a third of the budget, a decision that seems to have made the journey much deadlier for migrants packed into rickety vessels by traffickers who promise a better life in Europe.

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March 29, 2009: A boat overflowing with people rescued from three boats that sank in a violent storm off the coast of Libya arrive in the port of Tripoli. More than 200 were missing presumed deadAFP
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March 29, 2009: A man rests after arriving with other 63 sub-Saharan immigrants at La Tejita beach on the Spanish Canary island of TenerifeDesiree Martin/AFP
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February 5, 2009: Some 115 would-be immigrants await rescue on their boat after it ran into difficulties, 48 nautical miles off MaltaArmed Forces of Malta Air Wing/Reuters
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July 30, 2008: A group of 53 would-be immigrants in a half-submerged dinghy await rescue by the Armed Forces of Malta while sheltering against the hull of a cargo shipRohan Dalli /Maritime Squadron AFM/Reuters
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July 1, 2008: A man offer prayers of thanks after arriving at a beach on Spain's Canary island of Gran CanariaBorja Suarez/Reuters
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June 16, 2008: A boat used by would-be immigrants floats upside-down after capsizing, 75 miles south-west of Malta June 16, 2008. Twenty-seven people were rescued by the Italian trawler Altomare when their boat capsizedDarrin Zammit Lupi/Reuters
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May 21, 2007 :A small boat packed with 53 people drifts off Malta after its engine failedAFP
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August 3, 2006: First aid workers and tourists on a beach on the Spanish Canary island of Tenerife help African migrants suffering from the effects of their perilous voyageDesiree Martin/AFP
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May 5, 2006: A would-be immigrant crawls onto the beach after washing up in a makeshift boat on the Gran Tarajal beach on Spain's Canary Island of FuerteventuraJuan Medina/Reuters
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September 25, 2005: Members of the Maltese armed forces toss bottles of water to a group of around 180 illegal immigrants after their vessel ran into engine trouble, off the coast of MaltaDarrin Zammit Lupi/Reuters
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November 12, 2004: Migrants grab onto life preservers after their makeshift boat overturned during a rescue operation by Spanish authorities off the coast of FuerteventuraJuan Medina/Reuters
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November 12, 2004: Migrants try to climb aboard a Spanish civil guard vessel after their makeshift boat capsized during a rescue operation at sea off the coast of Fuerteventura. Of the 36 in the boat, 29 were rescuedJuan Medina/Reuters
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August 21, 2004: Beachgoers carrying a body walk past more bodies of would-be immigrants on the Fuerteventura coastJuan Medina/Reuters
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January 1, 2003: The body of a migrant who drowned after his makeshift boat capsized lies covered on El Matorral beach in Fuerteventura, Spain, as holidaymakers walk along the shoreJuan Medina/Reuters