Turkish efforts to stop traffickers from sending large "ghost ships" crammed with migrants towards Italy has sparked the surge in arrivals in Greece, the International Organisation for Migration says.
The migrants and refugees making the perilous journey across the Mediterranean to Europe are increasingly travelling the eastern route from Turkey to the Greek islands, which have seen more arrivals since the beginning of the year than long-time top destination Italy, according to UN figures.
IOM spokesman Joel Millman said on Thursday the main explanation for the surge in numbers of people arriving in Greece was a Turkish crackdown on traffickers' attempts to acquire large metal freighters to use as migrant "ghost ships" heading to Italy.
Towards the end of last year, traffickers began buying dilapidated freighters from scrap metal yards, filling them with hundreds of mainly Syrian refugees, and putting them on a GPS course towards Italy, with no crew onboard, he told AFP.
"We understand that quite a number of particularly Syrians were massed in Turkey waiting to go on one of these voyages, because they were directly bound for Italy and because the boats were considered much safer and much more sea-worthy than some of the boats that had gone out of Libya," Millman said.
Traffickers in some places even bought up cheap hotels to house migrants for what they expected would be a few days, but which turned into months after Turkey effectively blocked access to the freighters.
Thousands of people who had already paid traffickers to take them to Italy were thus stuck in Turkey with no way to get to their destination and no refunds offered.
In the end, Millman said, many appeared to agree to a compromise, allowing the traffickers to get them to Greece, which is much closer and can be reached on small dinghies.
The result has been clear. Some 124,000 refugees and migrants landed on the Greek islands during the first seven months of the year - up 750 per cent from 2014, according to UN figures.