Another 10,000 have been rescued so far in November, a time of year when the number of people risking dangerous trips normally slows to a trickle.
“Conditions were terrible in the last week, very harsh and that’s why there were so many shipwrecks,” IOM’s Italy spokesman Flavio Di Giacomo told NBC News. “We were quite surprised that so many boats had launched but when we interviewed the people afterwards they said smugglers had told them the EU was giving training to the Libyan coast guard and that in future they wouldn’t be rescued by European vessels but by Libyan ships and taken back to Libya.”
The development comes during a record-setting year as Europe grapples with an ongoing refugee crisis.
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Some 1,400 were rescued from at least 11 overcrowded boats on Tuesday, Italy's coast guard said. Rescuers also recovered eight bodies.
The rescue ship Vos Hestia, run by the international charity Save the Children, was among those involved in those rescues. It picked up more than 400 people from a wooden boat on Nov. 21, the organization said.
Those that don’t drown are often sickened by disease or toxic poisoning from the engines of overcrowded, unsafe ships.
Italy has faced the brunt of new arrivals since the implementation in March of an agreement between the European Union and Turkey to curb the flow of migrants sailing for Greece.
Di Giacomo said the winter spike was unlikely to ease because smugglers were exploiting fears that the popular Libya-to-Italy route would be closed off by the new patrols.
“These smugglers have very effective information campaigns — marketing, if you like — and they take advantage of this information to get more customers and to get more money,” he said.
“However, they told us that when they get over the border they are often beaten with sticks or not paid for the work they have done,” Di Giacomo said. “Eventually they think that their only escape is to Europe. In fact, when we rescued people from one shipwreck where many had died, some people said they were still more shocked by their treatment in Libya than by their ordeal at sea.”
Across the whole Mediterranean, 368,928 migrants have arrived in Europe so far in 2016, according to the IOM — including 345,676 by sea and 23,252 by land.
Alastair Jamieson is a London-based reporter, editor and homepage producer for NBC News.
Alexander Smith is a senior reporter for NBC News Digital based in London.