ANKARA/ATHENS (Reuters) - Turkey warned Greece on Wednesday to stay out of its activities in the eastern Mediterranean, heralding a potential showdown with Cyprus over hydrocarbons research in a region thought to be rich in natural gas.

Turkish research vessel Barbaros Hayrettin Pasa sails in the Bosphorus in Istanbul, Turkey March 6, 2017. Picture taken March 6, 2017. REUTERS/Yoruk Isik

Turkish Defence Minister Hulusi Akar said Ankara would not tolerate further Greek harassment of Turkish vessels after complaining last week that a Greek frigate had hassled a Turkish exploration ship west of Cyprus.

Greece, which has a defense protection pact with close ally Cyprus, denied the charge.

Attempts to tap hydrocarbons in the eastern Mediterranean, along with a dispute over Greece’s maritime borders, have revived tensions between Athens and Ankara - NATO allies who are separated by the Aegean Sea.

Turkey and the internationally recognized Greek Cypriot government in Cyprus have overlapping claims of jurisdiction for offshore oil and gas research in the eastern Mediterranean.

Both sides plan exploratory drills this year. Turkish officials earlier this month said a drill would take place in October.

“Our warships are providing the necessary protection in the region. We will never tolerate new harassment,” Akar told Turkey’s state Anadolu news agency. “We have (taken) all kinds of measures. I want everyone to know that we will not tolerate a fait accompli of any sort on this subject.”

Cyprus, which has no diplomatic relations with Turkey, accused Ankara of stirring up tensions.

“We are not going to go along with this artificial climate of tension which is trying to give an impression that there is a dispute,” Cypriot government spokesman Prodromos Prodromou said.

“There is no dispute in the seas of Cyprus.”

Breakaway north Cyprus, which is supported by Turkey, says any offshore wealth also belongs to them, as partners in the establishment of the Cyprus republic in 1960.

Greek Cypriots, who run the island’s internationally recognized government, say any future benefits of gas finds will eventually be shared by all Cypriots.

The island was split in 1974 after a Turkish invasion triggered by a brief Greek-inspired coup. Countless peacemaking endeavors have failed, and offshore wealth has increasingly been the elephant in the room of peace negotiations even though Greek Cypriots say that matter is not up for discussion.