President Recep Tayyip Erdogan announced Friday that Turkey has restarted a search for energy in the eastern Mediterranean, accusing neighbouring Greece of failing to keep its promises.
"We have resumed the drilling activity. We have sent (the vessel) Barbaros Hayrettin to the area," Erdogan told reporters after Friday prayers at Istanbul's landmark Hagia Sophia mosque.
Last month, Turkey said it had agreed to suspend "for a while" a search for oil and gas off a Greek island depending on the outcome of negotiations with Greece and EU heavyweight Germany.
"They haven't kept their promises," Erdogan claimed.
The search for hydrocarbons in the eastern Mediterranean has become a thorn in the relations between Turkey and the EU.
French President Emmanuel Macron has called for Turkey to be "sanctioned" and accused Ankara of treading on the rights of Greece and Cyprus, as all three nations scramble to exploit recently discovered gas reserves.
Greece condemned Turkey's plan to search for oil and gas off its shores as a violation of its sovereignty.
Ankara had claimed it is ready to negotiate with Athens without any preconditions.
Erdogan's comments come a day after Greece and Egypt signed an agreement to set up an exclusive economic zone in the eastern Mediterranean.
"This agreement has no value," the Turkish president said.
Egypt's foreign ministry spokesman Ahmed Hafez said on Thursday that the Turkish foreign ministry's rejection of the Egyptian-Greek maritime demarcation deal between the two countries is "surprising."
"It is surprising that such [Turkish] statements and allegations were issued by a party who had not originally seen the agreement and its details," Hafez wrote on his official Twitter account.
Turkey last year signed a deal with the Government of National Accord (GNA) in Libya on maritime jurisdiction, with several countries, including Egypt, Greece and Cyprus, accusing Ankara of trying to assert its dominance in the region.