UPDATED Monday, August 31: While Greece has extended its territorial waters by six nautical miles, fully within international rules, Turkey has responded by saying that the move is a reason for war. Using the Latin expression cases belli, Vice President Fuat Oktay said on Saturday: “You think we would accept such a thing? If this is not casus belli, then what is it?”

On Friday the Greek national defence agency claimed that Turkish fighter aircraft had entered the Athens Flight Information Region.

NATO chief Jens Stoltenberg called the Turkish president after the incident and urged dialogue and de-escalation. While both countries are NATO members, Greece’s EU partners are supportive. France has previously provided naval support for Greek manoeuvres.

Turkish President Erdogan has been accused by some observers of promoting neo-Ottoman ambitions. The part of the Mediterranean that Turkey claims is being called the Blue Homeland in pro-government Turkish media.

Turkey is showing no signs of heeding EU calls to abandon its controversial drilling plans, and the Turkish navy’s plans for ‘gunnery practice’ off Cyprus in the coming days could lead to a serious escalation in what is already a dangerous stand-off.

On Sunday, EU Minister of Foreign Affairs Josep Borrell took to France’s Le Journal de Dimanche to do some tough talking of his own. He said that Turkey, China and Russia, intend to “revive the memory of the great empires of the past”.

Borrell called for the birth of a stronger, “geopolitical Europe”.

“In order to be able to negotiate and settle conflicts peacefully, we must also learn to speak the language of power,” Borrell said.