US Noble Energy to search for oil and gas off Cyprus

Kassinis said the discovery raises optimism about the potential of gas being found inside Cyprus' zone, which covers 51,000 square kilometers (17,000 square miles) of seabed.

Greek Cyprus launched an initial licensing round in 2007. Kassinis said a second licensing round will be launched, but no specific date has been set.

Cyprus' oil and gas exploration bid has raised tensions with neighboring Turkey, which says it also has legal rights and interests in the area.

"Turkey has some fundamental rights and interests acknowledged by the United Nations in [those] marine areas. Turkey will naturally protect its rights," Foreign Ministry spokesman Burak Özügergin said in a statement on Friday. Under international law, the sea boundaries between the countries and the limits of the continental shelf of each country need to be delineated via a consensus among all coastal and neighboring countries when the issue is a semi-closed sea like the eastern Mediterranean. Since 2003, Greek Cyprus has sought to sign agreements with other coastal states to delineate the island's continental shelf in the Mediterranean, angering Turkey.

Greek Cypriot government spokesman Stefanos Stefanou said the island adheres to international law and would defend its rights "calmly, but with much determination and vigor," claiming "it's others who are violating the law."

Greek Cypriot officials last year accused Turkish navy ships of interfering with an offshore oil and gas survey off Cyprus' south coast.

Ankara also insists that Turkish Cypriots, who run their own state in the north of the island, should have a say in the island's oil and gas rights.

Turkish Cypriot Foreign Minister Hüseyin Özgürgün said last week oil and gas exploration could harm ongoing reunification talks.