ATHENS – Showing no signs of backing off, Turkey and Greece pressed competing claims to the Aegean and East Mediterranean seas where Turkey wants to hunt for energy and Greece wants to stop it.

Turkish President Recep Tayyip Erdogan had sent the energy research vessel Oruc Reis and 10 warships near the Greek island of Kastellorizo, a mile from Turkey's coast, and Greece responded with a Naval show of force, leading to a tense stalemate.

The tension ratcheted up when Prime Minister Kyriakos Mitsotakis  said Greece would move to extend territorial waters from six to 12 miles in the Ionian Sea off western Greece – and indicating he'd do the same in the Aegean and East Mediterranean, setting off Erdogan.

Mitsotakis said that would be done under the United Nations Law of the Sea that Turkey doesn't recognize unless invoking to its advantage, the Greek leader saying it would apply a median line where the distance between the two shores is smaller than 24 miles.

Turkey has warned that a similar move by Greece to the east would be a “casus belli” – a cause for war – with Erdogan also not recognizing the 1923 Treaty of Lausanne that set boundaries between the countries and coveting return of islands ceded to Greece, some so close to Turkey he said he could shout to them.

Greece on Aug. 26 held a second day of military exercises in the waters near the Turkish ships, further infuriating Erdogan who responded with fiery rhetoric saying Greece would be responsible if a conflict results.

To the alarm of western allies, both countries sent warships to shadow each other earlier in an area between Crete – where Turkey plans drilling – and Cyprus, where Turkey has been drilling, undeterred by soft sanctions from the European Union which has been timid about confronting Erdogan.

“Turkey will take what is its right in the Mediterranean, in the Aegean and in the Black Sea,” Turkish President Recep Tayyip Erdogan said. “Just as we have no eyes (on) anyone’s territory, sovereignty and interests, we will never compromise on what belongs to us. We are determined to do whatever is necessary in political, economic and military terms.”

Erdogan’s tough words came despite mediation efforts by Germany, whose Foreign Minister Heiko Maas conducted shuttle diplomacy between Athens and Ankara that failed.

"We invite our interlocutors to get their act together and to avoid mistakes that will lead to their ruin,” he said but neither Mitsotakis nor Erdogan paid the words any apparent heed.

Mitsotakis told Parliament that Greece was abandoning decades of “passive” foreign policy and its usual soft stance in dealing with Erdogan who has shown appeasement only emboldens him.

Turkey has warned in the past that an extension of Greek waters to 12 nautical miles in the Aegean Sea, facing the Turkish coast, would be seen as a reason to declare war on Greece.

BACK OFF!

Mitsotakis, speaking in Parliament, described Turkey's actions as “illegal and provocative” but he was still willing to talk as part of a German-brokered initiative — only if the Turkish seismic surveying work were halted.

“Our position is crystal clear and can be summarized in six words: When provocations stop, talks can start,” he said during a debate on the ratification of deals Greece recently made with Italy and Egypt setting out maritime boundaries and Exclusive Economic Zones.

That was a counter to an earlier agreement Turkey made with Libya dividing the seas between them, claiming waters in Greece's Continental Shelf and near Greek islands, including Crete – where the US Navy has a base on Souda Bay.

Mitsotakis' office said U.S. President Donald Trump phoned Mitsotakis “to discuss the recent developments in the southeastern Mediterranean,” after calling Erdogan, whom he calls a friend and “a hell of a leader.”

During the call, Mitsotakis “raised the issue of the destabilizing actions of Turkey that endanger peace and stability in the broader region and test the cohesion of NATO,” his office said.

Greece, he said, was prepared to contribute to de-escalating the situation “on condition Turkey immediately stops its provocative acts.”

Maas warned that “any spark, however small, could lead to a disaster,” a conflict accidental or otherwise which could bring an all-out war engulfing the region, NATO indicating it wants no part of it, the EU fiddling over what to do, the United Nations not even involved, and uncertainty which way the US would tilt.

After talks with Maas, the foreign ministers of both Greece and Turkey signaled readiness for dialogue but blamed each other for the standoff.

The Oruc Reis has for weeks been carrying out seismic research escorted by Turkish warships, Greece saying the ship is operating over Greece's Continental Shelf where it has exclusive rights on potential undersea gas and oil deposits, and sent warships to observe and track the Turkish flotilla.

Turkey disputes Greece’s claims, insisting that small Greek islands near the Turkish coast should not be taken into account when delineating maritime boundaries and said Greece wants an unfair share of the Eastern Mediterranean’s resources.

Turkey is also prospecting for hydrocarbons in waters where Cyprus claims exclusive economic rights, undeterred by soft sanctions from the EU and further undermining any prospects for reunification of the island where Turkey has occupied the northern third since an unlawful 1974 invasion.

“Everyone must see that Turkey is not a country whose patience can be tried, whose determination, capabilities and courage can be tested. If we say we’ll do something we’ll do it and pay the price.,” Erdogan said.

"If anyone wants to stand before us and face the consequences, they are welcome to. If not, stay out of our way and we will continue with our work.”

The Turkish leader spoke during an anniversary celebration marking the 1071 Battle of Manzikert, during which Seljuk Turks — who preceded the Ottoman Turks that later ruled the area — beat Byzantine forces, gaining entry into Anatolia. Greeks see themselves as the cultural heirs of the Byzantine Empire.

(Material from the Associated Press was used in this report)