The number of migrants reaching Greece hasn't abated, despite an agreement reached between the EU and Turkey to help stem the flow of people entering Europe, which went into effect at midnight Saturday.
In the night between Saturday and Sunday, 875 people arrived on Greek islands from the Turkish coast, Greek authorities said Sunday.
In the three days before, that figure varied between 239 and 1,498 people per day.
The deal between Turkey and the EU declared that those arriving on Greek shores can expect to be returned to Turkey as of midnight. The agreement hinges on a one-for-one swap of Syrian migrants, with the EU promising to resettle the same number of Syrians living in Turkey, up to a limit of 72,000.
According to the deal, migrants illegally entering Greece from Turkey will be returned to Turkey starting in April, unless they can prove that they would be subject to persecution there.
The authorities said there are currently 48,141 refugees in Greece, with about 7,316 on the nation's many islands in the Aegean Sea.
Around 13,000 are in Athens and its port, Piraeus, and the rest are in camps in central and northern Greece.
In the Turkish province of Izmir more than 3,000 migrants were stopped from crossing the Aegean Sea to Greece, with nearly 2,000 taken into custody in the district of Dikili on Saturday, CNN Turk reported Sunday.
Some of the detained - who are from Syria, Irak and Afghanistan - are being held in a sports hall and several have protested, breaking panes in the facility.
Greece needs an additional 4,000 employees to handle the influx of migrants, according to an estimate from the European Commission, the EU's executive body.
Handling asylum applications will require about 400 interpreters and 400 further refugee experts, and handling appeals to application decisions will require another 30 interpreters and 30 judges from other EU countries, the commission said.
Germany and France plan to send as many as 300 civil servants each to help with the situation.
A consultation with EU member states during the weekend on how to help Greece was promising and Greece can expect to receive help with the implementation of the EU-Turkey deal quickly, the commission said Sunday.