EU diplomatic chief Federica Mogherini on Saturday urged Turkey to reconsider plans to start exploratory drilling for oil and gas off Cyprus, already condemned as illegal by the European Union.

Greek officials are seeking closer ties to the U.S. military, a move that occurs as Turkey refuses to back down on acquiring a Russian air defense system that could compromise NATO aircraft.

In the event that the United States refuses to supply Turkey with F-35 fighter jets, Ankara will satisfy its needs elsewhere, Turkish Foreign Minister Mevlut Cavusoglu told Russian news agency Sputnik.