The Greek navy said nobody was hurt in the collision late on Monday, the second such incident in a month, which it blamed on "dangerous manoeuvres" by the Turkish boat.

The Greek boat, which was financed with European funds "to monitor Greek seas and European borders", suffered damage, the navy said.

The incident occurred near the uninhabited Imia islets, just off the Turkish coast and a historic flashpoint in a long-running demarcation dispute.

A similar incident occurred last month, when the Greek navy said the two vessels' sides "came together... probably owing to an error on the part of the Turkish vessel".

Greek Prime Minister Alexis Tsipras complained about the latest incident to his Turkish counterpart Binali Yildirim, who initiated a phone call between the two on Tuesday.

Tsipras told Yildirim that such collisions undermine relations between the two countries as well as between Turkey and the EU, and violate international law, the Greek prime minister's office said in a statement.

Tsipras stressed "the need to immediately stop Turkish violations" of Greek territory in the Aegean and "de-escalate tensions", the statement said.

The office of the Turkish prime minister said Yildirim told Tsipras that Turkey was concerned by the development and Greece should take "the necessary steps to de-escalate the tensions".

Both sides agreed that top Turkish and Greek military officials could meet to discuss the situation, if required, said a source who asked not to be named.

- Turkey-EU row over Cyprus gas -

The rising tensions came as EU President Donald Tusk on Tuesday urged Turkey to "avoid threats or actions against any EU member" after Turkish warships blocked an Italian drilling vessel seeking to begin exploration for gas off Cyprus.

Turkey's President Recep Tayyip Erdogan then warned foreign energy companies not to "overstep the mark" in the Mediterranean.

Greek government spokesman Dimitris Tzanakopoulos said Athens was "troubled" by Turkey's behaviour.

"There is tension in Turkey, problems that Mr Erdogan and his government are having trouble dealing with, and a general destabilisation in the area surrounding Turkey," Tzanakopoulos told Alpha radio.

"(Turkey) is not helping to smoothe out the turbulence, it's doing the opposite," he said.

The Imia islets -- called Kardak in Turkey -- lie just seven kilometres (4.5 miles) from the Turkish port of Bodrum.

A row over their sovereignty flared in January 1996, when the two countries sent marines to two neighbouring islands.

They withdrew their troops after heavy diplomatic pressure by the United States, a fellow member of NATO.