Greek authorities are throttling the transport of migrants from Aegean islands to the mainland in a bid to relieve the pressure of people piling up at the nearly closed border with Macedonia, an official said Friday.
"We must slow the influx because of the backlog on the mainland," Shipping and Islands Minister Thororis Dritsas told TV Skai.
Fewer ferry tickets will be sold to migrants, and fewer ferries will be sent to the islands where migrants arrive from Turkey. With that, they will "wait a little longer" before continuing their journey following the registration process, Dritsas said.
In order to avoid burdening the islands, the migrants will be sheltered on ferries docked in the ports of Lesbos, Chios and Samos, he added.
According to Greek authorities, 20,000 migrants are stranded in the country, while 4,000 are waiting at the border.
The stranding of migrants in Greece has come after Macedonia and other countries down the so-called Balkan route - Serbia, Croatia, Slovenia and, finally, Austria - on Sunday stopped admitting Afghans.
People are still moving north through Greece, avoiding overcrowded refugee centres, in hope that they will squeeze through and resume the journey toward wealthy EU countries, most of all Germany.
But the pace of even Syrians and Iraqis being allowed in has slowed in recent months due to barriers imposed by Greece's neighbours, and resulting in further backlogs in Greece.
Afghans are the second-largest group, after Syrians, in the migration surge that brought more than 1 million people to Europe through Greece and the Balkan route over the previous 12 months.
Countries north of Greece had been waving them through alongside Syrian and Iraqi refugees until the decision to stop them, which angered Greece and further strained relations within the European Union as it struggles to find an answer to the migration crisis.