Greece says Turkish boats forced migrants into its waters
Athens regularly blames Ankara for not taking sufficient action to curb smugglers who send out migrants in unsafe boats and dinghies from its shores in breach of a 2016 accord with the EU.
The European Union and Ankara signed a deal in March 2016 where Turkey was to sharply reduce the flow of migrants through its territory to EU countries Bulgaria and Greece in return for billions of euros in financial aid.
Both Greece and Turkey have accused the other of failing to honour the agreement sealed after more than a million migrants and asylum seekers entered the EU in 2015.
"The video shows without a doubt the efforts of Turkish coast guard vessels to make dangerous manoeuvres to guide the dinghy to Greek waters... east of Lesbos," the coast guard said in a statement, accompanied by the video.
"Once again Turkey has behaved like a 'pirate state' in the Aegean Sea, breaching its engagements with the European Union," Greek Maritime Affairs Minister Giannis Plakiotakis said.
Prime Minister Kyriakos Mitsotakis accused Turkey of "instrumentalising migration" during talks with his Dutch counterpart Mark Rutte, who is on an official visit to Athens.
"Yes, we are intercepting boats that come from Turkey, as we have the right to do in accordance to the European regulation, and waiting for the Turkish coast guard to come and pick them up to return them to Turkey," Mitsotakis said to a reporter's question about alleged Greek pushbacks.
"So rather to put the blame on Greece you should put it on those who have been instrumentalising migration systematically."
The one-minute video seen by AFP shows two Turkish ships making a sharp manoeuvre in front of a dinghy carrying at least 15 migrants.
The ships and the dinghy are then seen turning back towards the Turkish coast.
The video was made public five days after a German MEP, Cornelia Ernst, visited the Greek island of Samos with a team to probe Greece's handling of migrants.
Ernst said the team had found five Somali migrants, who were hiding after arriving the previous night, and handed them over to the Greek police.
"It is clear for me that by finding them and handing them over physically to the Greek police a potential pushback was prevented," she said in a tweet.
"I have read too many well documented reports of push backs to believe that they would have been able to ask for asylum if we had not been there," Ernst added.
Greek Migration Minister Notis Mitarachi has ordered a probe.
Greece's tough border controls have been dogged by accusations from rights groups that the Greek coastguard has been engaging in illegally forcing migrants to return to Turkey, the main departure point, on rickety vessels.
Athens has consistently denied the charges, insisting that saving lives at sea is a priority for the Greek coastguard.