Cyprus on Sunday accused Turkey of "piracy" after Ankara announced new plans to drill for oil and gas in the divided island´s maritime zone.
"Turkey is turning into a pirate state in the eastern Mediterranean," the presidency said in a statement.
"Turkey insists on going down the path of international illegality it has chosen," it added.
On Friday, Ankara announced the drillship Yavuz would return to waters off Cyprus for drilling activities, a day after President Recep Tayyip Erdogan vowed Turkey would start gas exploration "as soon as possible".
Cyprus said Turkey was now attempting to drill inside an exploration area, or block, south of the ethnically split Mediterranean island nation that's already licensed to energy companies Eni of Italy and Total of France.
This would be Turkey's fourth such drilling effort since last July when it dispatched a pair or warship-escorted drill ships to the island's west and east, and would also mark the second time a Turkish ship was drilling in a block licensed to Eni and Total, the Associated Press reported.
EU has warned Turkey earlier that it would impose "targeted and appropriate" sanctions if it did not stop its "illegal activities".
For its part, Ankara says its actions abide by international law and that it is drilling inside its continental shelf.
On Sunday Turkey further called on the EU to end what it said was the bloc's prejudice against Turkish Cypriots.
"The EU has remained silent since 2003 to the usurping of our country's and the Turkish Cypriots' rights in the eastern Mediterranean," Turkish Foreign Ministry spokesman Hami Aksoy said in a written statement.
"The European Union must firstly end these policies under the guise of union solidarity, which are far from reality, prejudiced and show double standards," he added.
The island has been divided between the internationally recognised Republic of Cyprus and the northern third under Turkish control since 1974, after Ankara's troops occupied the area in response to a coup sponsored by the Greek military junta, according to AFP.
