Greece said on Tuesday that the EU must impose sanctions against Turkey if it does not back down on exploration for natural resources in the Mediterranean. Turkey and Greece are at odds over claims for resources, and EU member Cyprus is also exploring for natural gas in the Eastern Mediterranean amid strong objections from Ankara. A navigational advisory was issued by Turkey’s navy on Tuesday for seismic survey work in an area south of Turkey’s Antalya, between Cyprus and Crete. The advisory is in effect until August 20. “Turkey is unfortunately adding another link in hostile actions against Greece, against Cyprus and the EU as a whole,” Greek Prime Minister Kyriakos Mitsotakis told German Foreign Minister Heiko Maas, who was visiting Athens. “Questioning the sovereign rights of Greece and Cyprus is, ultimately, questioning the rights of Europe. "We anticipate the support of our allies. As long as Turkey continues to take this path, sanctions on Turkey will be a one-way street.” Turkey says it is within its sovereign rights to explore for resources in areas it considers to be its its continental shelf, or within self-proclaimed maritime boundaries. Greece and Turkey have had testy relations for decades, with occasional flare-ups. There was a sharp exchange of words this year when thousands of refugees and migrants hosted by Turkey tried to force their way though a land border with Greece that Ankara declared open. They also disagree over ethnically partitioned Cyprus. Greece has been angered at a deal between Libya and Turkey carving out maritime boundaries that skim its southern island of Crete, paving the way for potential resources exploration.