Almost 400 migrants disembarked on Sunday from a Turkish-flagged cargo ship that Greece allowed to dock in its territory despite claiming Turkey breached a deal made in 2016.
The ship sent a distress signal on Friday after its engines failed in international waters off Crete, said Greek authorities who allowed it to dock at the south-eastern Aegean island of Kos early on Sunday.
The Greek Coastguard said the migrants were taken to a reception centre on the island where Health Ministry experts put them in quarantine and tested them for the coronavirus.
The Migration Ministry said 382 people disembarked from the ship, with six of them detained for questioning.
Migration Minister Notis Mitarachi told ERT TV that the migrants were mainly from Pakistan and Bangladesh. The channel said some were also from Afghanistan.
Mr Mitarachi said Greece was frustrated with Turkey's refusal to call back the ship, even though it knew it had set sail.
"We have notified the EU that Turkey has refusing to take their vessel back," he said.
"Greece has rescued hundreds of thousands of people in the last seven years. It is time for the EU to act and provide impactful solidarity and ensure the EU-Turkey statement is upheld."
Brussels and Ankara signed a deal in March 2016 where Turkey was to sharply reduce the flow of migrants through its territory to Bulgaria and Greece, in return for billions of euros in financial aid.
Greece and Turkey have accused each other of failing to honour the agreement sealed after more than a million migrants and asylum seekers entered the EU in 2015.
The Greek islands of the eastern Aegean are a first EU port of call for waves of migrants and asylum seekers coming through Turkey.
On Tuesday, four migrants, two of them children, drowned after a boat sank off the island of Chios.
The vessel had set out from Turkey during strong winds, and none of the occupants had been given a life vest by the smugglers, the Greek Coastguard said.