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handout photo via AP, Italian Navy
The migrant ship that sank off Sicily last year with an estimated 700 people onboard is being recovered by the Italian Navy, Tuesday, June 28, 2016. The navy says it's raised the boat toward the surface from a depth of more than 1200 feet. The wreck is being kept in a refrigerated transport structure for the trip back to land, where forensic experts will begin trying to identify the victims.

ROME — The Italian navy has raised from the seafloor the migrant ship that sank off Sicily last year with an estimated 700-800 people aboard in one of the worst known tragedies of the Mediterranean migrant crisis.

The navy said it had had successfully recovered the boat from a depth of 370 meters (1,214 feet) using a complicated pulley system fixed to a support frame that attached onto the shipwreck. Now resurfaced, the wreck is being kept in a refrigerated transport module for the trip back to port in Sicily, where forensic experts will begin trying to identify the dead.

A press conference to explain details of the operation is scheduled for Thursday, the navy said.

The April 18, 2015 wreck remains one of the deadliest on record, though the real number of drownings will never be known. On that night, the boat carrying between 700 and 800 migrants, most of them African, capsized as a civilian freighter approached.

Most passengers were locked below decks; only 28 survived.

The sinking sparked renewed outrage and soul-searching in European capitals, which agreed to send in EU naval reinforcements to cast a wider safety net to try to rescue the waves of migrants leaving Libya on smugglers' boats.

While tens of thousands have been rescued, thousands of others have drowned: During one particularly deadly three-day period last month, an estimated 700 migrants died, including those aboard a huge, overcrowded fishing ship that capsized as rescuers filmed the horror.

The U.N. refugee agency estimates that from April 19, 2015 to today, some 4,927 people have perished making the sea crossing to Europe.

Most of the migrant boats that sink are never recovered, and the dead are never exhumed or identified. Soon after the 2015 tragedy, though, Italy pledged to recover the wreck and is hoping that the exercise will help create a European network to identify victims by cross-checking data.

The navy launched the complicated recovery operation this past spring; navy divers over the previous months had already recovered some 169 bodies found near the wreckage, located some 85 miles (130 kilometers) off Libya's coast.

The navy submerged a giant yellow-framed rectangular apparatus to stabilize the wreck and affix support legs to its hull. Pulleys then raised the frame and vessel to the surface for the tow operation into port.

Italy's southern islands are the main destinations for countless numbers of smuggling boats launched from the shores of lawless Libya packed with people seeking jobs and safety in Europe.

Humanitarian organizations and investigating authorities typically rely on survivors' accounts to piece together how many people may have been killed during a capsizing, relying on overlapping accounts to try to establish a level of veracity.

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