Arrivals of refugees and migrants to Greece from Turkey rose sharply on Wednesday, just over a week since the European Union and Turkey struck a deal intended to cut off the flow.
Greek authorities recorded 766 new arrivals between Tuesday morning and Wednesday morning, up from 192 the previous day.
Most arrived on the northeastern Aegean island of Lesvos.
Italy reported an even larger jump in arrivals on Tuesday, when officials there said 1,350 people - mostly from Africa - were rescued from small boats taking the longer migration route over the Mediterranean as the weather warmed up.
The EU Commission said on Tuesday that the flows in the last week had reduced, with only 1,000 people arriving from Turkey on Greek islands, compared to an average of 2,000 a day in the last couple of months.
It was not clear why numbers had dropped, but the Aegean Sea had been hit with bad weather and gale force winds, making the journey from Turkey on small rubber boats even more dangerous.
Under the deal in effect since March 20, migrants and refugees who arrive in Greece will be subject to being sent back once they have been registered and their individual asylum claim processed. The returns are to begin from April 4.
More that 51,000 refugees and migrants, among those Syrians, Afghans, Iraqis and other fleeing conflict in the Middle East and Asia, are currently stranded in Greece following border closures across the Balkans.
Nearly 6,000 people remain stuck at the country's biggest port of Piraeus port near Athens, having arrived there on ferries from Greek islands close to Turkey before the deal.
Scores have found shelter in passenger waiting lounges while hundreds more sleep in the open, either in flimsy tents or on blankets spread on the dock.
Queues for the few portable toilets are long, and scuffles have broken out in recent weeks over mobile phone chargers and food distribution.
International rights group Human Rights Watch has described conditions at the port, including basic hygiene, as “abysmal” and says the situation is akin to a “humanitarian crisis.”
Among those stranded in Piraeus on Wednesday was Mariam El Musa, a 37-year-old teacher from Aleppo, Syria. “The problem here is the psychology of the people,” she said.
“People are angry and depressed because the borders are closed, because it takes ages to have a meal and because we are dirty, we can't have a shower. We Syrians thought we would stay in Greece for only two-three days.”
A fellow Syrian hoping to reach Holland, 24-year-old Haisam Mahli, has spent the last three weeks at the port, after landing on the Aegean island of Chios from Turkey a month ago.
He plans to join a protest march to central Athens later on Wednesday against the EU-Turkey deal.
“We will protest to parliament to help open the borders and improve conditions here,” he said.