Cypriot President Nicos Anastasiades briefed fellow EU leaders in Sibiu on the issue of Turkish drilling | Jack Taylor/Getty Images EU warns Turkey over oil drilling in Cypriot waters Greece and Cyprus urged EU to address alleged Turkish violation of exclusive economic zone.

SIBIU, Romania — EU leaders warned Turkey on Thursday to respect the sovereign rights of Cyprus amid a growing dispute over a Turkish oil drilling ship that entered Cypriot territory in the eastern Mediterranean.

Cypriot President Nicos Anastasiades briefed fellow EU leaders on the issue at a summit in Romania.

"Today President Anastasiades also informed the leaders about the Turkish drilling activities within the exclusive economic zone of Cyprus," Council President Donald Tusk said at the summit's closing news conference. "The European Union stands united behind the Republic of Cyprus and expects Turkey to respect sovereign rights of the EU member states. The European Council will continue to follow these developments closely."

Greek Prime Minister Alexis Tsipras said he stands firmly behind Cyprus and urged Turkey to refrain from provocations.

"We had the chance together with President Anastasiades to highlight as a core issue of today's summit the illegal actions of Turkey within Cyprus' exclusive economic zone," Tsipras said. "I completely supported the position of the president of Cyprus, who asked for this issue to be confronted as a European issue and I pointed out that the European Union has a special geopolitical and energy interest in the area of eastern Mediterranean."

Tsipras said he had urged the EU to consider "the steps and necessary actions and measures, if this unilateral, provocative behavior and violation of international law continues. Turkey must understand that it should sit and discuss instead of continuing its unilateral violations of international law."

He added: "We want a Mediterranean region of peace and cooperation, and not a Mediterranean of violations of international law. And this is not a Greek and Cypriot position, it's a European position."