Greece has accused Turkey of undermining efforts to ease a crisis over eastern Mediterranean drilling rights.
The charges come after Ankara redeployed a survey vessel for new energy exploration in disputed waters – including an area very close to a secluded Greek island.
The move reignited tension over sea boundaries between Greek islands, Cyprus and Turkey’s southern coast which had flared up over the summer, prompting a military build-up, bellicose rhetoric and fears of a confrontation between the two Nato members and historic regional rivals.
The Turkish search vessel, Oruc Reis, left the port of Antalya on Monday. An international maritime safety advisory, or Navtex, issued late on Sunday said the exploration would last until October 22.
This new unilateral act is a severe escalation on Turkey’s partGreek Prime Minister Kyriakos Mitsotakis
Turkish defence minister Hulusi Akar said the vessel was continuing with its “planned and scheduled activities,” adding that the Turkish navy would provide “support and protection” if necessary.
Greek Prime Minister Kyriakos Mitsotakis discussed the development on the phone with European Council president Charles Michel, saying he would bring it up at the next council meeting on October 15-16.
“This new unilateral act is a severe escalation on Turkey’s part,” a government statement quoted Mr Mitsotakis as saying.
On Monday, Turkey said Greek objections to Orus Reis’ redeployment were “unacceptable”, insisting that the search vessel was operating within Turkey’s continental shelf – an area nearly 10 miles away from the Turkish coast and about 265 miles away from mainland Greece.
“Our expectation from Greece is for it to withdraw its maximalist claims that are contrary to international law … put an end to its exercises and military activities that increase tensions in the Aegean and the Mediterranean and to enter into a sincere dialogue with us,” the Turkish Foreign Ministry said.
Turkey faces the threat of sanctions from the European Union, which has sided in the dispute with member states Greece and Cyprus.
German foreign minister Heiko Maas, whose country holds the rotating EU presidency and has been mediating between Ankara and Athens, will fly to Cyprus and Greece for talks on Tuesday.
On Monday, the German government said it had “taken note” of Turkey’s announcement on the energy prospecting.
“If there really were exploration in this disputed area of sea, that would be a very regrettable step and, from our point of view, an unwise one,” German Chancellor Angela Merkel’s spokesman, Steffen Seibert, told reporters in Berlin.
“It would set back efforts to reduce tensions in the eastern Mediterranean and it most certainly would be anything but conducive to the continued development of EU-Turkish relations.”