The long-running dispute between Turkey and Greece, both NATO members, flared up after the two countries reached rival agreements on their maritime borders with Libya and Egypt, and Turkey sent this month a research vessel into the disputed waters.
Both sides have conducted military exercises in the eastern Mediterranean, bringing thus to attention the potential for disagreement over the extension of their continental shelf which risks escalating into a clash.
Two weeks ago, Greek and Turkish frigates following the Turkish oil and gas exploration ship Oruç Reis collided, and the Turkish Defense Ministry said on Thursday that Turkish F-16s had prevented the entry of six F-16s of Greece in an area where Turkish vehicles were operating.
On Friday evening, Turkey issued a Navtex announcement, an advisory message to sailors, saying it would hold a "weapons exercise" from Saturday to September 11th in northwestern Cyprus.
The top European Union diplomat said on Friday that the bloc was preparing sanctions against Turkey that could be discussed at a summit in late September in response to Ankara's stance on Greece, a European Union member state.
Turkish Vice President Fuat Oktay criticized possible measures, which could be imposed on individuals, ships or the use of European ports in an effort to limit Ankara's exploration capabilities.
"It is insincere for the EU to seek dialogue on the one hand and make other plans on the other, regarding the activities we carry out on our continental shelf in the eastern Mediterranean," he said on Twitter.