Greek–Turkish relations

Byzantine territory (purple), Byzantine campaigns (red) and Seljuk campaigns (green).

In 1048 conflicts between Seljuqs and Byzantines (Greeks were dominant nation of the Byzantine Empire and the Empire was Hellenized) started. Many wars and battles were fought between the Byzantine and the Seljuq armies. Also, in the 1300s, conflicts between Ottomans and Byzantines started.

In 1453, Ottomans conquered Constantinople, the capital city of the Byzantine Empire. In 1460 they conquered the Despotate of the Morea, in 1461 the Empire of Trebizond, in 1475 the Principality of Theodoro and by 1500 most of the plains and islands were in Ottoman hands. Holdouts included Rhodes, conquered in 1522, Cyprus in 1571, Crete, retained by the Venetians until 1669, and the Ionian islands which remained primarily under the rule of the Republic of Venice.

During the Ottoman–Venetian Wars and the Russo-Turkish War (1768–74) Greece provided aid to Ottoman rivals. Dionysius the Philosopher additionally organised several uprisings. In addition, the Lambros Katsonis fleet began harassing the Ottoman fleet in the Aegean Sea.

In 1770, the Ottoman army invaded the Mani.

In the 1803, 1807 and 1815 the Ottoman army invaded Mani. Also during this period, in 1803 there was a final fight between the Souliotes and the local Ottoman ruler, Ali Pasha, which ended the many years of conflicts between them.

The first Ottoman ambassador to the Greek Kingdom, the Phanariote Konstantinos Mousouros, at a ball in the royal palace in Athens

In March 1821, the Greek War of Independence from the Ottoman Empire began. The Greeks formally declared their independence in January 1822, and after the Battle of Navarino in 1827, the establishment of a Greek state was recognized in the London Protocol of 1828. The first borders of the Greek state consisted of the Greek mainland south of a line from Arta to Volos plus Euboea and the Cyclades islands in the Aegean Sea. The rest of the Greek-speaking lands, including Crete, Cyprus and the rest of the Aegean islands, Epirus, Thessaly, Macedonia and Thrace, remained under Ottoman rule. Over one million Greeks also lived in what is now Turkey, mainly in the Aegean region of Asia Minor, especially around Smyrna, in the Pontus region on the Black Sea coast, in the Gallipoli peninsula, in Cappadocia, in Istanbul, in Imbros and in Tenedos.

Greek politicians of the 19th century were determined to include all these territories within a greatly enlarged single Greek state, based on the Byzantine model and with Constantinople (Istanbul) as its capital. This policy was called the Great Idea (Megali Idea). Constantinople had been the capital of the Eastern half of the Roman Empire until its fall to the Turks in 1453. The Ottomans naturally opposed these plans for a larger Greek state. The Empire was considered by the European powers as 'the sick man of Europe', but since these powers were irreconcilably divided over the fate of the Ottoman lands, the conflicts both reduced its territorial hold but also kept delaying its collapse.

During the Crimean War (1854 to 1856), Britain and France prevented Greece from attacking the Ottomans by occupying Piraeus. They were again prevented from taking military action during the Russo-Turkish War of 1877, in which the Greeks were keen to join in with the objective of territorial expansion, but Greece was unable to take any effective part in the war. Nevertheless, after the Congress of Berlin, in 1881 Greece was given most of Thessaly and part of Epirus. Also, in 1854–1896, there were revolts in the Ottoman Empire by the Greek population in Thessaly, Macedonia, Epirus.

In 1858–1896, there were many revolts in Crete, Thessaly Macedonia and Epirus against the Ottoman Empire by the Greek population.

Ethnic map of Asia Minor depicting the Ottoman Greeks (blue) in 1910

In 1897, a new revolt in Crete led to the first Greco-Turkish War. An unprepared Greek army was unable to dislodge the Ottoman troops from their fortifications along the northern border, and with the resulting Ottoman counter-attack, the war resulted in minor territorial losses for Greece.

The Young Turks, who seized power in the Ottoman Empire in 1908, were Turkish nationalists whose objective was to create a strong, centrally governed state. The Christian minorities of the Empire, including Greeks, saw their position in the Empire deteriorate.

The First Balkan War of 1912–1913 was a direct consequence of the mounting tension, as a result of which Greece seized Crete, the islands, the rest of Thessaly and Epirus, and coastal Macedonia from the Ottomans, in alliance with Serbia and Bulgaria. Crete was once again the flashpoint for tension between the two nations.

Greece entered the First World War in 1917 with the intention of seizing Constantinople (Istanbul) and Smyrna (İzmir) from the Ottomans, with the encouragement of the British and French governments, who also promised the Greek government enosis with Cyprus at a certain stage. The ongoing genocide of Pontic Greeks in the Ottoman Empire also played a factor in this decision. Although there was little direct fighting between Greeks and Turks, when the Ottoman Empire collapsed in 1918 the Greeks were quick to claim the lands the Allies had promised them. The 1920 Treaty of Sèvres gave Greece eastern Thrace and an area of about 17,000 km² in western Anatolia around Smyrna. This Treaty was signed by the Ottoman government but never went into force, not having been ratified by Parliament.

Greece occupied Smyrna/İzmir on 15 May 1919, while Mustafa Kemal Pasha (later Atatürk), who was to become the leader of the Turkish opposition to the Treaty of Sèvres, landed in Samsun on May 19, 1919, an action that is regarded as the beginning of the Turkish War of Independence. He united the protesting voices in Anatolia and set in motion a nationalist movement to repel the Allied armies that had occupied Turkey and establish new borders for a sovereign Turkish nation. Having created a separate government in Ankara, Kemal's government did not recognise the abortive Treaty of Sèvres and fought to have it revoked. The Greek advances into Anatolia were eventually checked and the Greek army was forced into retreat.

Overcrowded boats with refugees fleeing the Great fire of Smyrna. The photo was taken from the launch boat of a US warship.

The Turkish army entered Smyrna/İzmir on 9 September 1922, effectively ending the Greco-Turkish War (1919-1922) in the field. The Greek army and administration had already left by sea. The war was put to an end by the Armistice of Mudanya, and the Treaty of Lausanne (1923) replaced previous treaties to constitute modern Turkey.

The Treaty of Lausanne (1923) also provided for a Population exchange between Greece and Turkey that had begun before the final signature of the treaty in July 1923. About one and a half million Greeks had to leave Turkey for Greece and about half a million Turks had to leave Greece for Turkey (note that the population exchange was on religious grounds, thus the exchange was officially that of Christians for Muslims). The exceptions to the population exchange were Istanbul (Constantinople) and the islands of Gökçeada (Imbros) and Bozcaada (Tenedos), where the Greek minority (including the Ecumenical Patriarch) was allowed to stay, and Western Thrace, whose Muslim minority was also allowed to stay.

Due to the defeat of the Greek army and the events following which terminated 3,000 years of Greek presence in Anatolia, Greece refers to it as the Asia Minor Catastrophe/Disaster. Greek accusations were focused on the Great Fire of Smyrna, especially in view of the account provided by George Horton, the U.S. Consul General in the city from 1919 to 1922.[1] Horton's account remains as controversial as the fire itself.[2][3]

The Treaty of Lausanne (1923) awarded the islands of Imbros and Tenedos to Turkey, under special provisions for the Greeks living there. Tenedos population was overwhelmingly Greek, and Imbros population was entirely Greek. However, after the legislation of "Civil Law" on 26 June 1927, the rights accorded to the Greek population of Imbros and Tenedos were revoked, in violation of the Lausanne Treaty. Thus, the island was demoted from an administrative district to a sub-district which resulted that the island was to be stripped of its local tribunals. Moreover, the members of the local council were obliged to have adequate knowledge of the Turkish language, which meant that the vast majority of the islanders were excluded. Furthermore, according to this law, the Turkish government retained the right to dissolve this council and in certain circumstances, to introduce police force and other officials who were non-islanders. This law also violated the educational rights of the local community and imposed an educational system similar to that followed by ordinary Turkish schools.[4]

During the Corfu incident between Italy and Greece, at 1923, elements in Turkey advised Mustafa Kemal to seize the opportunity to invade Western Thrace.[5]

The first president of Turkey Mustafa Kemal Atatürk (center) hosting Greek Prime Minister Eleftherios Venizelos (at left) in Ankara October 27, 1930

The post-war leaders of Turkey and Greece, Kemal Atatürk and Eleftherios Venizelos respectively, were determined to establish normal relations between the two states. After years of negotiations, a treaty was concluded in 1930, and Venizelos made a successful visit to Istanbul and Ankara. Greece renounced all its claims over Turkish territory. This was followed by the Balkan Pact of 1934, in which Greece and Turkey joined Yugoslavia and Romania in a treaty of mutual assistance and settled outstanding issues (Bulgaria refused to join), embassies were constructed as a result. Both leaders, recognising the need for peace resulted in more friendly relations, with Venizelos even nominating Atatürk for the Nobel Peace Prize in 1934.[6]

Kemal Atatürk with Ioannis Metaxas in Ankara, March 1938

In 1941, Turkey was the first country to send humanitarian aid to Greece to relieve the great famine in Athens during the Axis occupation. Turkish president İsmet İnönü signed a decision to help the people whose army he had personally fought during the Turkish War of Independence 19 years earlier. Foodstuffs were collected by a nationwide campaign of Kızılay (Turkish Red Crescent)and sent to the port of İstanbul to be shipped to Greece. The aid was shipped on board the vessel SS Kurtuluş with big symbols of the Red Crescent painted on both sides. (See SS Kurtuluş for more information.)

At the same time, Turkey signed a "Treaty of Friendship and cooperation" with Nazi Germany to avoid invasion in June 1941.[7] The following year, 1942, Turkey imposed the Varlık Vergisi, a special tax, which taxed the non-Muslim minorities of Turkey, including Greek minority. Also, during the WWII there was the incident of the Twenty Classes, this was the conscription of non-Muslims males who were sent in labour battalions.

The early Cold War brought closer the international policies of the two countries, in 1950 both fought at the Korean War at the side of the UN forces. In 1952, both countries joined NATO. In 1953 Greece, Turkey and Yugoslavia formed a new Balkan Pact for mutual defence against the Soviet Union.

A serious matter of conflict in Turkish-Greek relations since the 1950s has been Cyprus; at the time, it was a British colony with a Greek-Cypriot population share of 82%. Some of the Greek Cypriots wanted union (enosis) with Greece and, as early as 1931, there were nationalist riots in Nicosia. The Greek government, due to its financial and diplomatic dependence on Britain, demurred from officially expressing support for unification with Cyprus.

In the 1950s, the Cyprus issue flared up again when the Greek Cypriots, under Archbishop Makarios, claimed union with Greece, and the EOKA group launched a paramilitary movement on the island – primarily against the British administration, but also inflicting collateral damage to other parties and civilians. Eventually, Greek Prime Minister Alexander Papagos took the Cyprus issue to the United Nations.

Turkish nationalist sentiment, angered by the discrimination against the Turkish Cypriots, became inflamed at the idea that Cyprus would be ceded to Greece. This led to the Greek community of Istanbul becoming the target in the Istanbul Pogrom of 1955. In response, Greece withdrew from all co-operation with Turkey, which caused the Balkan Pact to collapse.

In 1960, a compromise solution to the Cyprus issue was agreed on: Britain granted independence to Cyprus, and a constitution was hammered out. Greek and Turkish troops were stationed on the island to protect their respective communities. Greek Prime Minister Constantine Karamanlis was the main architect of this plan, which led to an immediate improvement in relations with Turkey, particularly once Adnan Menderes was removed from power in Turkey.

During the period of intercommunal strife in 1963 and 1964, Greek and Turkish Cypriots were displaced and many were massacred on both sides.

On 30 December 1964, Makarios declared his proposal for a constitutional amendment that included 13 articles. Turkey, however, restated that she was against this and threatened war if Cyprus tried to achieve unity with Greece. In August, Turkish aircraft bombed Greek troops that surrounded a Turkish village (Erenkoy) and war seemed imminent. Once again, the Greek minority in Turkey suffered from the crisis, causing many Greeks to flee the country, and there were even threats to expel the Ecumenical Patriarch. Eventually, intervention by the United Nations led to another compromise solution.

In 1964 Turkish prime minister İsmet İnönü renounced the Greco-Turkish Treaty of Friendship of 1930 and took actions against the Greek minority.[8][9] Turkey enforced strictly a long‐overlooked law barring Greek nationals from 30 professions and occupations, for example Greeks could not be doctors, nurses, architects, shoemakers, tailors, plumbers, cabaret singers, ironsmiths, cooks, tourist guides, etc.[8] Many Greek have been ordered to give up their jobs after this law.[10] 50,000 more Greeks were expelled.[11] They were given a week to leave the country. Deportees protested that it was impossible to sell businesses or personal property in so short of a time. Most of those deported were born in Turkey and they had no particular place to go in Greece.[8] Greeks had difficulty getting credit at banks. Those expelled, in some cases, could not dispose of their property before leaving.[10] Also, Turkey forcefully closed the Prinkipo Greek Orthodox Orphanage,[12][13][14] the Patriarchate's printing house[10] and the Greek minority schools on the islands of Gökçeada/Imbros[15] and Tenedos/Bozcaada.[16] Furthermore, the farm property of the Greeks on the islands was taken away from its owners[16] and university students organized boycotts against Greek shops.[10] Teachers of schools maintained by the Greek minority complained of frequent “inspections” by squads of Turkish officers inquiring into matters of curriculum, texts and especially the use of the Greek language in teaching.[10] In the same year the Turkish Foreign Minister, Feridun Cemal Erkin, in an interview appeared to imply that the Dodecanese closest to Turkey's Asia Minor coast should have been turned over to Turkey to preserve Greco‐Turkish friendship.[17]

The Cyprus dispute weakened the Greek government of George Papandreou and triggered, in April 1967, a military coup in Greece. Under the diplomacy of the military regime, there were periodic crises with Turkey, which suspected that the Greek regime was planning a pro-unification coup in Cyprus.

Northern Cyprus in 2009

A 1971 Turkish law nationalized religious high schools and closed the Halki seminary on Istanbul's Heybeli Island which had trained Greek Orthodox clergy since 1844.

On July 15, 1974, a band of Greek Cypriot nationalists formed EOKA B, advocating Enosis (Union) with Greece and, backed by the Greek military junta in Athens, staged a coup against the Cypriot President and Archbishop Makarios. An ex-EOKA man, Nikos Sampson was appointed president. On July 20, Turkey—using its guarantor status arising from the trilateral accords of the 1959–1960 Zürich and London Agreement—invaded Cyprus without any resistance from the British forces based on the island, occupied 37% of the northern part and expelled the Greek population. Once again, war between Greece and Turkey seemed imminent, but actual war was averted when Sampson's coup collapsed a few days later and Makarios returned to power. Also, the Greek military junta in Athens, which failed to confront the Turkish invasion, fell from power on 24 July. The damage to Turkish-Greek relations was done, and the occupation of Northern Cyprus by Turkish troops would be a sticking point in Greco-Turkish relations for decades to come.

• On 18 June 1992, a Greek Mirage F1CG crashed near the island of Agios Efstratios in the Northern Aegean, during a low-altitude dogfight with two Turkish F-16s. Greek pilot Nikolaos Sialmas was killed in the crash.[19]
• Οn 8 February 1995, a Turkish F-16C crashed on the sea after being intercepted by a Greek Mirage F1CG. The Turkish pilot Mustafa Yildirim bailed out and was rescued by a Greek helicopter. After brief hospitalization in Rhodes, the pilot was handed over to the Turkish side.[20]
• On 27 December 1995, a pair of Greek F-16Cs intercept a pair of Turkish F-4E. During the dogfight that followed, one of the Turkish aircraft went into a steep dive and crashed into the sea, killing its pilot Altug Karaburun. The co-pilot Ogur Kilar managed to bail out safely and was rescued by a Greek ΑΒ-205 helicopter. He was returned to Turkey after receiving first aid treatment in Lesbos.[19]
• On 8 October 1996, a pair of Greek Mirage 2000s intercepted a pair of Turkish F-16s (a single-seater C and a two-seater D) over the Aegean island of Chios. The F-16s were escorting 4 Turkish F-4Es on a simulated SEAD mission. After a long dogfight, one of the Turkish F-16s was allegedly shot down with a Magic II missile fired by a Greek Mirage 2000 piloted by Thanos Grivas.[19] The Greek authorities said that the jet went down due to mechanical failure, while the Turkish Defense Ministry said, on 2014, that the jet had been shot down by the Greek pilot.[21][22][23] Some Greek media outlets reported that it was an accident and the Turkish plane had unintentionally been shot down.[24][21] Turkish pilot Nail Erdoğan was killed whereas back seater pilot Osman Cicekli bailed out. He was rescued by a Greek helicopter and handed over to the Turkish side. Greece officially offered to assist Turkey in its efforts to locate and salvage the Turkish fighter jet.[22] On 2016, Turkish prosecutors have demanded two aggravated life sentences for the Greek pilot who allegedly downed the Turkish F-16 jet. The indictment demanded that Greek Mirage 2000 pilot Thanos Grivas be sentenced to two aggravated life sentences on charges of “voluntary manslaughter” and “actions for weakening the independence of the state.” It also demanded another 12 years for “vandalizing the jet.”[25] Greece rejected the demands of the Turkish prosecutors.[26]
• On 23 May 2006, a Greek F-16 and a Turkish F-16 collided approximately 35 nautical miles south off the island of Rhodes, near the island of Karpathos during a Turkish reconnaissance flight involving two F-16Cs and a RF-4.[27][28] Greek pilot Kostas Iliakis was killed, whereas the Turkish pilot Halil İbrahim Özdemir bailed out and was rescued by a cargo ship.
• On 16 February 2016, Turkey prevented the Greek PM's aircraft carrying the Greek PM and Greece's delegation from landing on the island of Rhodes for refueling during their trip to Iran, arguing that the island is a demilitarized zone. Turkey also refused to accept the flight plan submitted by the Greeks, mentioned that the plane will not be allowed to enter Turkish airspace. Greeks created a new flight plan, the plane flew over Egypt, Cyprus, Jordan and Saudi Arabia so as to reach Iran, according to the new plan.[29]
• On 12 February 2018, near midnight, the 1700 ton SG-703 Umut of the Turkish Coast Guard rammed into the 460 ton Stan Patrol OPV-090 Gavdos of the Hellenic Coast Guard.[30] No injuries were reported but Gavdos received considerable damage on her port stern side. The incident took place in Greek territorial waters east of Imia.
• On 12 April 2018, a Greek Air Force Mirage 2000-5 fighter jet crashed into the Aegean Sea, killing the pilot Capt. Giorgos Baltadoros, 33, as he returned from a mission to intercept Turkish aircraft that had violated Greek air space. The Hellenic Air Force lost contact with the Mirage jet at 12.15, while the aircraft was about 10 miles northeast of Skyros.[31]
• On 17 April 2018, two Turkish fighter aircraft harassed the helicopter carrying Greek Prime Minister and the Greek Armed Forces Chief, as they were flying from the islet of Ro to Rhodes. The Turkish jets contacted the pilot of the Greek helicopter and asked for flight details. The Hellenic Air Force (HAF) responded by sending its own jets, which caused the Turkish fighters to leave.[32]
• On 25 March 2019, the Greek Prime Minister accused Turkey of harassing his helicopter while he was traveling to Agathonisi for the Greek independence day celebration. Turkey rejected the accusations, saying that the fighter jets were carrying out a routine mission.[33]
• On 18 April 2019, Anadolu Agency wrote that after some foreign media claimed that Turkish fighter jets harassed the helicopter which was carrying the Greek army general during its travel to Kastelorizo, the Turkish army dismissed the claims saying that there was no approach that posed a danger to the Greek helicopter, adding that the aircraft belonging to the Turkish Air Forces were on regular duty in the Aegean.[34]
• In March 2020, Greece summoned Turkey's ambassador to lodge a complaint after the Greek coastguard said one of its vessels had been rammed deliberately by a Turkish coastguard boat.[35]
• On 3 May 2020, Greek officials said that two Turkish fighters harassed the helicopter which was transferring the Greek Defense Minister and the Greek Chief of the National Defense General Staff, after the helicopter took off from the island of Oinousses. In response 2 Mirage 2000s were sent to intercept the Turkish F-16s which was caught on video and released by the Hellenic air force. The Greek Ministry of Defense provided photos of the incident showing the Turkish aircraft.[36][37]

In 1986, Turkish and Greek soldiers suffered casualties at the Evros River incident, due to fire exchange. Turkish and Greek soldiers have exchanged fire in the past, as Greeks have tried to stop Iranian refugees from entering the country illegally from Turkey, but this incident was the first in which there have been casualties. During this period, Greek soldiers along the border with Turkey were on alert after receiving reports that Turkey planned to help thousands of refugees slip into Greece illegally.[38][39] After the incident, top military and civilian authorities from both countries met to discuss a border protocol aimed at preventing future confrontations.[40]

In 1955 a Turkish usher at the Turkish consulate in Thessaloniki planted a bomb, which was sent from Turkey. The Turkish press accused the Greeks for the bomb and an organised mob attacked the Greek minority of Istanbul resulting in Istanbul pogrom.

During the 2010 trial for an alleged plot to stage a military coup dating back to 2003, named Sledgehammer, the conspirators were accused of planning attacks on mosques, triggering a conflict with Greece by shooting down one of Turkey's own warplanes and then accusing Greeks of this and planting bombs in Istanbul to pave the way for a military takeover.[61][62][63]

After the failed July 2016 Turkish coup d'état attempt, several Turkish military personnel sought political asylum in Greece while Turkey requested their extradition. Also, the Greek armed forces and Coast Guard were on alert and increased the patrols and a contingent of the Greek Police was dispatched to some Greek islands to conduct checks there in order to prevent the arrival of participants in the failed coup to Greece and arrest anyone who might manage to enter the country.[96][97][98]

Also, the two Turkish military attaches in Athens fled to Italy. The Greek Foreign Ministry cancelled the two attaches accreditations on August 7, 2016, upon the request of the Turkish Foreign Ministry. At August 11, 2016, the Turkish Foreign Minister Mevlut Cavusoglu said that they left Greece to Italy on August 6 and added that Turkey will officially ask Italian authorities to extradite the two soldiers.[99][100]

On August 25, 2016, seven Turkish citizens were seeking asylum in Greece. A couple, both of whom are university professors, and their two children applied for asylum in Alexandroupoli after they illegally entered the country from the northeastern border. Also, three businessmen have illegally reached the Greek island of Rhodes, and they also applied for asylum.[101][102]

On August 30, 2016, a Turkish judge arrived to the Greek island of Chios on a migrant boat and sought asylum in the country. He told the Greek coast guard and police officers that he is being persecuted in Turkey for his political beliefs by the government of President Tayyip Erdogan. The Turkish judge had been arrested for illegally entering the country and, also, he transferred to Athens for his asylum proceedings.[103][104][105][106]

On September 21, 2016, ten Turkish civilians, two men, two women and six children landed by boat illegally on the Greek island of Rhodes and sought asylum. They told the Greek authorities they were working in the private sector in Turkey and they were being persecuted by the Turkish government due to their political beliefs.[107][108]

On September 29, 2016, five Turkish nationals, a couple and their child and two other men, arrived in Alexandroupolis by crossing the Evros River by boat illegally and requested political asylum.[109]

On 15 February 2017, five Turkish commandos illegally entered Greece through the Evros river. However, once they entered the country, the group split. Two of them surrendered to the police and on 20 February 2017, requested political asylum. The Greek government announced that the Greek authorities will not allow the country to be dragged into the ongoing feud between the Turkish state and the followers of Gulen.[110][111] But there was no sign of the other three. According to a lawyer, there were indications that the other three had been arrested by Greek authorities who were about to expel them to Turkey. Later, according to new evidence and new information these three “arrested” marines were delivered under fast and informal procedures from Greek to Turkish services.[112][94]

On October 24, 2017, Turkish authorities obtained information that 995 Turks have applied for asylum in Greece after the coup attempt.[113] More than 1,800 Turkish citizens requested asylum in Greece in 2017.[114]

On March 27, 2017, the former editor in chief of the English version of the Turkish newspaper Zaman, Abdullah Bozkurt, posted a tweet on his account warning of increased clandestine operations of Turkish intelligence agents in Greece.[115]

On August 16, 2017, Turkish Foreign Minister Mevlut Cavusoglu speaking before Turkey's National Assembly, said that a number of interconnected problems remain in the Aegean between the Turkey and Greece. “Among these problems is the question of sovereignty of certain islets and rocky formations, and the fact that there are no sea borders which are set by an international agreement between Turkey and Greece,” he said.[116]

On August 22, 2017, the Erbakan Foundation (a religious foundation) at Sinop staged a protest, demanding the removal of a statue of the ancient Greek philosopher who was born at Sinop, Diogenes, from the city entrance. The foundation said it was protesting the fact that the Greek ideology being attached to the province.[117]

In December 2017 Recep Tayyip Erdogan became the first Turkish president to visit Greece in 65 years.[118] Also, the Republican People's Party (CHP) leader Kemal Kılıçdaroğlu in a speech at the parliament criticized Recep Tayyip Erdoğan over his "failure" to raise the issue of "18 occupied islands" during his visit to Greece. His political party also declared the Turkish names of 156 islands, islets and reefs in the Aegean Sea and claimed them as Turkish territory. The Greek Defense minister, Panos Kammenos, responded "come and get it". Kılıçdaroğlu then said, that Turkey will come and take all of those islands back, while the CHP's deputy leader for foreign affairs, Öztürk Yılmaz, said that "Greece should not test our patience".[119][120]

On April 10, 2018, Greek soldiers fired warning shots at a Turkish helicopter approaching the island of Ro. The helicopter was flying at a very low altitude late at night with its navigation lights switched off.[121]

On April 16, 2018, Turkish Prime Minister Binali Yıldırım said that on April 15, Greek citizens planted a Greek flag on an uninhabited rocky islet at the Aegean, but the Turkish coast guard removed the flag. In addition, urged the Greek government to refrain from “provocative moves” in the "disputed areas" of the Aegean Sea. The Greek government responded that there was no evidence indicating "violation of Greek territory" and labeled the claims as "totally provocative and reprehensible".[122][123]

In August 2018, the former lawmaker for the Peoples' Democratic Party (HDP), Leyla Birlik, requested asylum in Greece after illegally crossing the border near Alexandroupolis.[124]

In September 2018, the Turkish Agriculture and Forestry Ministry warned Turkish fishers not to enter the territorial waters of Greece. “In order to prevent unwanted incidents and accidents, and to abstain from activities that would harm our country’s legal and political theses and ones which we would be unable to explain or defend,” after several complaints were handed to Turkey's Foreign Ministry saying Turkish fisher boats had entered Greece's territorial waters.[125]

On November 27, 2019, Turkey and Libya signed a deal. The agreement, unveiled on December 5, maps out a sea boundary between the two countries, cutting across a part that is also claimed by Greece.[133] Greek Foreign Minister Nikos Dendias called the Turkey-Libyan accord a "blatant violation of international law". Greek authorities were taken by surprise by the accord, after Libyan officials assured them the deal would not be signed off.[134] Greece on December 6 expelled the Libyan ambassador. Mitsotakis told the Greek parliament “They are oblivious to history and geography as they do not take Greek islands into account,” adding that Ankara's move is forcing them into “unprecedented diplomatic isolation”.[135] Turkey condemned Greece's decision to expel the Libyan ambassador.[136][137]

In December, Greece sent two letters to the United Nations explaining its objections and asking for the matter to be taken up by the U.N. Security Council,[138] while Turkey notified the United Nations of its delimitation of the maritime jurisdiction areas with Libya. The United Nations remained neutral[139] and urged Greece and Turkey to maintain a dialogue.[140] The head of the Tobruk parliament (Libya's eastern-based parliament) expressed his disagreement over the agreement during a visit to Greece.[141][142] Greece followed by establishing a legal maritime accord with Egypt, while maintaining its legal right to implement a 12-mile maritime by law that is currently only 6.

In early 2020, western security officials reported a pattern of cyber attacks against governments and other organizations in Greece and other European and Middle Eastern countries in late 2018 and early 2019, which they described as resembling a "state-backed cyber espionage operation conducted to advance Turkish interests". Turkey's officials declined to comment.[143]

In early 2020, Greek authorities released a number of videos apparently showing Turkish Coast Guard vessels harassing Greek ones and escorting migrants and refugees into Greece, in the northeast Aegean Sea.[144][145]

On June 10, 2020, a Greek frigate under the command of the European Union's Operation Irini attempted to inspect the Tanzanian-flagged cargo vessel Çirkin which was suspected of carrying arms to Libya, but was ordered to retreat after warnings from Turkish frigates accompanying the cargo vessel.[146][147][148][149] Later, Turkish navy also stopped a French warship from the NATO Operation Sea Guardian from inspecting the vessel.[150] On 21 September 2020, the EU sanctioned the Turkish maritime company Avrasya Shipping which operates the Çirkin freighter, because the vessel found to have violated the arms embargo in Libya in May and June 2020.[151]

On November 22, 2020, the German frigate Hamburg intercepted a Turkish freighter near Libya and soldiers from the frigate boarded the Turkish ship in order to search it, but had to abandon checks and withdraw after Turkey protested. Turkish President Erdoğan accused Greece for “provocations” because the man in charge of the operation during that incident was a Greek official.[152] European Union in an official statement said that the inspection followed the internationally agreed procedures, including NATO procedures and that the Irini operation is in accordance with the UN Security Council Resolutions 2292 (2016) and 2526 (2020) and that the UN Security Council Resolution 2292 (2016) calls upon all flag States to cooperate with inspections. These resolutions are binding for all UN Member States, including the Turkey.[153]

In mid-August 2020, tensions between the two countries have risen after Turkey sent a survey vessel RV MTA Oruç Reis to the region, escorted by warships, to map out sea territory for possible oil and gas drilling in an area where Turkey and Greece both claim jurisdiction.[154] On 25 August 2020, it was reported that Greece and Turkey are planning rival naval exercises off Crete amid an escalating row over energy claims in the region.[155] Greek media have reported that purchases consisting of French-made Rafale fighter jets and at least one French frigate will be made.[156]

Greece accused Turkey's authorities that on 14 October weren't granting permission to the plane of the Greek Foreign Minister to fly through the Turkish airspace, back to Greece from Iraq. The plane was kept circling over Mosul for 20 minutes before Turkish authorities grant it permission. According to the Turkey's Foreign Ministry, the first plane that carried Greek Foreign Minister to Iraq broke down before going back to Greece, and Greece assigned another plane. The second plane hadn't provided the required flight plan, and after the plan was received from the Iraqi authorities the flight was carried out safely.[157]

In September 2020, RV MTA Oruç Reis returned back toward shore to ease tensions.[158] However, the EU decided to impose sanctions on Turkey in December 2020, over its gas drilling activies and foreign policy in general.[159]

In January 2021, the two countries resumed talks on maritime disputes along with other issues in Istanbul, ending a five-year hiatus.[160]