Turkey said on Monday that its Oruc Reis exploration vessel will now carry out seismic surveys in a disputed part of the eastern Mediterranean until Sept. 12, in a move likely to stoke tensions in the region.

Turkey and Greece, 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 east Mediterranean, highlighting the potential for the dispute over the extent of their continental shelves to escalate.

The Turkish navy issued a new advisory saying that the work of the Oruc Reis would continue until Sept. 12. It had previously been scheduled to work until Sept. 1.

The advisory referred to a specific exploration area. But 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 Sept. 11