NICOSIA, Cyprus (AP) — The prime minister of Greece says Turkey's ongoing drilling for gas in waters where Cyprus has exclusive economic rights is a sign of "weakness."

Greek Prime Minister Alexis Tsipras warned Tuesday of "grave consequences" for Turkey's relations with the European Union and for regional stability if the Turkish government persists.

Tsipras said "everyone knows" that Turkey's "futile" exploration in waters where Cyprus has economic rights and there is no naval deterrent indicated weakness on Ankara's part.

Turkey says it's protecting its rights and those of breakaway Turkish Cypriots to the area's energy reserves.

A Turkish drillship is operating off Cyprus' west coast. Turkey has dispatched a second vessel to drill off the Mediterranean island nation's east coast.

EU leaders have condemned the actions and warned of sanctions.