Greece signed a 2.3 billion-euro ($2.8 billion) deal with France on Monday to purchase 18 Rafale fighter jets, as tensions remain high with neighbor Turkey. Florence Parly, the French defense minister, signed the agreement in Athens to deliver 12 used and six new aircraft built by Dassault Aviation over two years, starting in July. France has sided with Greece in a dispute over boundaries in the Aegean Sea and eastern Mediterranean that has brought NATO members Greece and Turkey to the brink of war several times in recent decades. Tension spiked again last summer when a Turkish exploration mission in disputed waters triggered a dangerous military buildup. Greece and Turkey have agreed to restart talks aimed at resolving the dispute peacefully. Senior diplomats from the two countries met in Istanbul on Monday to resume the process that had been interrupted for nearly five years. But Athens says it will continue a multibillion-euro program to upgrade its military following years of cuts because of the countrys financial crisis. France and the United States are in competition to provide the Greek navy with new frigates, while Greeces government recently approved plans to cooperate with Israeli defense electronics firm Elbit Systems to create a new military flight academy in southern Greece. “The upgrade in the capabilities of the Hellenic Air Force by means of both the acquisition of new fighter aircraft and the new state-of-the-art training center is critical for Greece to present a credible deterrence,” Michael Tanchum, a senior fellow at the Austrian Institute for European and Security Policy, told The Associated Press. “It also provides Athens an enhanced ability to exercise more strategic autonomy when EU and NATO frameworks are deemed inadequate, making Greece more of a player in its own right.” Starting in May, mandatory national service in the Greek Armed Forces will be increased from nine to 12 months to boost the number of people serving in uniform. Parly, who also met Greek Prime Minister Kyriakos Mitsotakis, announced that France would join two Greek military exercises later this year, participating with Rafale jets from the French air force.