The first boats carrying migrants being deported from Greece to Turkey have departed under an EU plan aimed at easing mass migration to Europe.
Scores of migrants were seen boarding ferries on the Greek island of Lesbos early on Monday.
They are being sent to Dikili, western Turkey. Turkish officials said they expected to receive around 500 people.
The EU-Turkey deal has been attacked by rights groups and there are concerns over a lack of preparation.
Migrants in Greece have complained of a lack of information about the asylum procedure and some said they were unaware they could be returned.
The EU agency responsible for escorting people back across the Aegean has less than one-tenth of the staff needed to do the job, the Associated Press reported.
Another ferry carrying migrants to Turkey is also due to leave the Greek island of Chios on Monday.
The vice-mayor of Lesbos told the BBC that 136 people had left the island so far, most from Pakistan.
Under the deal, migrants arriving illegally in Greece are expected to be sent back to Turkey if they do not apply for asylum or if their claim is rejected.
For each Syrian migrant returned to Turkey, the EU is due to take in another Syrian who has made a legitimate request.
Turkey won financial and political concessions as part of the agreement.
The arrangement has alarmed rights groups, who say Turkey is not a safe country for migrants.
Amnesty International has accused Turkey of illegally returning Syrians to their homeland, something Turkey denies.
Save the Children called the deal “illegal and inhumane”, saying people told them they would kill themselves if sent back to Turkey.
