Turkey says its Oruc Reis exploration vessel will carry out seismic surveys in a disputed area of the eastern Mediterranean until September 12, provoking an angry response from neighbouring Greece.
The two NATO allies vehemently disagree over claims to hydrocarbon resources in the area based on conflicting views on the extent of their continental shelves in waters dotted with mostly Greek islands.
Both sides have held military exercises in the eastern Mediterranean, highlighting the potential for the dispute to escalate.
The Turkish navy announced the extension of the Oruc Reis’s mission late on Monday – it was previously scheduled to end on September 1.
The advisory came after the European Union’s executive earlier on Monday called for dialogue with Turkey and demanded that Ankara refrain from unilateral steps that stoke tensions in the eastern Mediterranean.
Greece’s foreign ministry called the advisory illegal and urged Turkey to ease tensions and work for stability in the region.
“Turkey continues to ignore calls for dialogue and to escalate its provocations,” the ministry said in a statement. “Greece won’t be blackmailed.”
Greece will keep seeking maritime deals with its neighbours in the region, based on international law and the law of the Sea, the ministry added.
Last week, Greece ratified an accord on maritime boundaries with Egypt, following a similar agreement signed between Turkey and Libya.
Turkey’s latest advisory referred to a specific exploration area. On Saturday, Turkish Foreign Minister Mevlut Cavusoglu said the Oruc Reis would continue working for the next 90 days as it moved gradually closer to the Turkish province of Antalya.
Seismic surveys are part of preparatory work for potential hydrocarbon exploration.
Turkey has also been exploring for hydrocarbon resources in the Black Sea and discovered a 320-billion cubic metre (11.3 trillion cubic feet) gas field.
Separately, Turkey also said it will hold a military exercise off northwest Cyprus until September 11.
Last week, the EU said it was preparing to impose sanctions on Turkey – including tough economic measures – unless progress is made in reducing soaring tensions with Greece and Cyprus in the eastern Mediterranean.
Turkish Vice President Fuat Oktay slammed the EU threat as “hypocritical”.