Turkish President Recep Tayyip Erdogan issued a warning Tuesday to neighboring Greece, Cyprus and international companies exploring for gas in the eastern Mediterranean not to "step out of line" and encroach on Turkey's rights.
Meanwhile, Greek authorities said a Turkish coast guard vessel rammed a Greek coast guard boat off a couple of uninhabited islets in the Aegean Sea over which the two NATO allies nearly went to war in 1996. There were no injuries.
Erdogan made the warning in an address to legislators of his ruling party as Turkish warships continued to impede a rig from reaching a location off of Cyprus where Italian energy company Eni is scheduled to drill for gas.
"We recommend that foreign companies don't allow themselves to be an instrument of issues that surpass their limits and strength, by trusting the Greek Cypriot side," he said. "Their show of strength lasts only until they see our ships and our planes."
Turkey opposes the drilling, which it says disregards the rights of breakaway Turkish Cypriots. It also claims as its own part of the area Cyprus has designated for exploratory drilling.
The Cypriot government says it has a sovereign right to drill, and that if the search is successful, any income would be shared equitably if the island is reunified.
Cypriot President Nicos Anastasiades refrained from direct comment on Erdogan's statements, but said Turkish naval activity should cause no public alarm.
"There's no reason for anyone to worry," he told reporters in Nicosia. "Actions are being taken in such a way so as to avert any kind of crisis."
European Commission spokesman Margaritis Schinas said EU authorities are monitoring the incident in the Agean closely.
He said Turkey needs to "commit unequivocally" to good neighborly relations and avoid any "friction, threat or action" against an EU member state.
Cyprus has been divided since Turkey invaded in 1974, after a failed coup by supporters of union with Greece. The island joined the EU in 2004, but only the southern part enjoys full membership benefits.
Many in Turkey also dispute Greek ownership of uninhabited Aegean islets near Turkey's coastline. The two countries have a long history of rivalry, and have thrice come close to war over Aegean rights and Cyprus since 1974.
"Opportunistic attempts concerning gas exploration off Cyprus and concerning Aegean islets are not escaping our attentions," Erdogan said.
Greece's coast guard said nobody was injured in the collision, which took place around midnight Monday, although the Greek vessel suffered damage to the stern where the Turkish boat hit it with its bows.
A coast guard statement said the Turkish vessel was conducting "dangerous maneuvers," and struck the Greek vessel inside Greek waters.
The coast guard vessels were east of the uninhabited islets — known as Imia in Greek and Kardak in Turkish — which both countries claim and are prime fishing spots, attracting fishing boats from both countries.
Greek government spokesman Dimitris Tzanakopoulos voiced concern but appealed for restraint.
"Right now there is no need to pour more oil on the flames. What is needed is calm, level-headedness and a serious handling of the situation," he said.
"Recently we have been seeing increasingly provocative behaviour from Turkey, which is a source of very serious concern to us," he told private Alpha radio.
The Turkish ambassador in Athens was summoned to the Greek Foreign Ministry for explanations.
Tension around the islets has remained high since the two NATO allies came to the brink of war over them more than 20 years ago, when they deployed their navies to the spot and a Greek helicopter crashed into the sea, killing three crewmen.
Paphitis contributed from Athens, Greece. Menelaos Hadjicostis in Nicosia, Cyprus, and Lorne Cook in Brussels contributed.Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.