Geopolitical tensions between Greece and Turkey

Athens. A power cable, warships and an Israeli air defense system: What at first glance seems to have little to do with each other, forms a dangerous geopolitical puzzle in the eastern Mediterranean.

Greece and Turkey, both NATO members, are again making accusations. The phase of detente that began after Turkish President Recep Tayyip Erdogan's visit to Athens at the end of 2023 is over.

What particularly worries Turkey is Greece's alliance with Israel - a country that the Turkish head of state repeatedly castigates as a "terrorist state". At the end of August, the governments in Athens and Jerusalem agreed on an arms program worth billions. Israel is to equip Greece with a multi-layered air defense system against aircraft, missiles and drones. The project is called “Shield of Achilles”.

From Athens' perspective, it serves as a deterrent. For Ankara it looks like encirclement - especially since the Republic of Cyprus, the northern part of which Turkey has occupied militarily since 1974, is now also purchasing modern weapons systems from Israel.

The cooperation between Greece, Israel and Cyprus extends beyond arms deliveries and joint military maneuvers. A planned power cable in the eastern Mediterranean is causing additional tension. The Great Sea Interconnector (GSI) is intended to connect the power grids of the three countries. The EU wants to support the strategically important energy project with 658 million euros.

But Turkey is going against it. The cable is supposed to run through a maritime area that Turkey claims as its own economic zone. The government in Ankara argues that the line should therefore only be relocated with the express permission of Türkiye. Greece and Cyprus reject Turkish territorial claims. Turkish approval is not required.

The dispute is not new. When the Italian research vessel “Ievoli Relume” carried out survey work south of the island of Kasos on behalf of the Greek power grid operator IPTO in the summer of 2024, Turkey showed up with five warships.

Greece responded by sending a frigate and coast guard patrol boats. The ships of the two NATO partners lay ready for combat for 40 hours. Then the “Ievoli Relume” withdrew.

The episode showed how quickly an infrastructure project can lead to a military confrontation. There could be a risk of a repeat of the crisis in the next few weeks: The GSI consortium wants to resume survey work in the disputed sea areas shortly. The majority shareholder in the cable project is now the French infrastructure investor Meridiam. This means that France is now also coming into political play in the controversy over the cable route.

The more actors are involved, the more complicated the situation becomes. In recent months, Greece has integrated Israel, Cyprus and France ever more closely into its security and energy policy. Defense Minister Nikos Dendias wants to invest around 30 billion euros in new weapon systems by 2036: frigates, submarines, stealth jets and drones. In addition to the USA and Israel, France is one of the important suppliers.

Turkish Foreign Minister Hakan Fidan accuses Greece, Cyprus and Israel of forming an “alliance against Turkey”. In Ankara, the increasingly close military cooperation with Israel is seen as particularly threatening against the backdrop of the Turkish-Israeli confrontation in Syria.

This particularly applies to the planned stationing of Israeli weapons systems on the Greek Aegean islands. As part of the “Shield of Achilles” program, Greece plans to install mobile air defense and rocket launcher systems of the Israeli types Spyder, Barak MX, David’s Sling and Puls.

They are designed to fend off aircraft, cruise missiles, drones and artillery shells. Ankara fears that the Greek islands off the Turkish coast would become Israeli outposts.

The Greek military is also working on setting up drone bases on the islands of Rhodes and Lesbos. Foreign Minister Fidan sees the armament of the Greek islands as a “security threat” for his country. From Turkey's point of view, Greece is violating the Treaties of Lausanne (1923) and the Paris Peace Treaty of 1947. They restrict the military use of certain Greek Aegean islands.

Athens points to its right to self-defense guaranteed in the UN Charter. In addition, the Turkish doctrine of the “Blue Homeland” is now exacerbating the conflict. It defines extensive Turkish territorial claims in the Aegean and the Eastern Mediterranean. The Turkish government is working on a law that will incorporate the doctrine into Turkish law. The bill could be submitted to parliament in Ankara this month.

From the perspective of the government in Athens, the question of Greek territorial waters is now back on the agenda. Greece currently claims a six-mile zone in the Aegean Sea, but reserves the right to extend it to twelve miles, citing the UN Convention on the Law of the Sea.

The issue is explosive: there is a resolution by the Turkish parliament from 1995, according to which Turkey views an expansion of Greek territorial waters as a “casus belli” (ground for war).

Greek Prime Minister Kyriakos Mitsotakis warned against “unilateral actions and threats of war” at the UN General Assembly at the end of September. His country wants to continue the dialogue, but on the basis of international law. Erdogan was unexpectedly conciliatory before the forum: He emphasized that Turkey is “not an enemy” of Greece, but a neighbor and NATO ally.

Western diplomats in Athens and Ankara agree: Neither government wants to risk open war. The greater danger is an acute crisis that spirals out of control - for example if a Turkish warship pushes away a research ship or fighter jets dangerously clash over the Aegean. This could quickly turn into a confrontation that is difficult to control.