The launch of a second Turkish drillship destined for Cypriot waters has angered the European Union.
The vessel will drill for gas off Cyprus' east coast, despite the EU preparing for a possible sanctions over the issue, AP reported.
The 230-metre Yavuz can reach depths of 12km.
Another Turkish drillship is already working 40 miles off the island's west coast.
Cyprus has condemned the Turkish action as a violation of international law.
EU leaders meeting in Brussels spoke of the "immediate negative impact that such illegal actions have across the range of EU-Turkey relations."
They plan to "submit options for appropriate measures without delay, including targeted measures."
EU Commission president Jean-Claude Juncker said they "will not be soft measures."
Turkish energy minister Fatih Donmez said his country would defend its rights and those of breakaway Turkish Cypriots.
He pledged to continue drilling without interruption.
Cyprus has promised to share potential gas proceeds with Turkish Cypriots after a reunification deal.
