Greece should avoid statements and moves it will regret, President Recep Tayyip Erdoğan said late Thursday as tensions between the two neighbors are high following a series of disagreements.

Erdoğan warned Greece to demilitarize islands in the Aegean Sea, posting tweets in Greek and English, in a marked harshening of rhetoric.

"We warn Greece to stay away from dreams, statements and actions that will lead to regret, as it did a century ago, and to come to its senses," the Turkish leader said. A hundred years ago, Turkey defeated Greece after a three-year war that saw Greek armies invade western Turkey.

"We leave it to the international community to decide what it means to demand 40,000 kilometers (24,850 miles) of maritime jurisdiction for Meis island, which is less than 2 kilometers from our country's mainland but more than 600 kilometers from Greece in the Eastern Mediterranean."

Turkey is demanding that Greece demilitarize its eastern islands, maintaining the action is required under 20th-century treaties that ceded sovereignty of the islands to Greece.

The Greek government calls the demand a deliberate misinterpretation and has accused Turkey, a fellow NATO member, of stepping up hostile actions in the area.

Starting from the Treaty of London in 1913, the militarization of the eastern Aegean islands was restricted and their demilitarized status was confirmed with the signing of the Treaty of Lausanne in 1923. The Lausanne pact established a political balance between the two countries by harmonizing vital interests, including those in the Aegean.

The 1947 Treaty of Paris, which ceded the Dodecanese islands from Italy to Greece, also confirmed their demilitarized status.

However, Greece argues that the 1936 Montreux Convention on Turkish Straits should be applied in this case, while Ankara says Greece's obligation to disarm the islands remains unchanged under the Montreux Convention, highlighting that there is no provision that differentiates it from the Treaty of Lausanne on the issue.

Turkey, which has the longest continental coastline in the Eastern Mediterranean, has rejected maritime boundary claims made by EU members Greece and the Greek Cypriot administration, stressing that these excessive claims violate the sovereign rights of both Turkey and the Turkish Republic of Northern Cyprus (TRNC). Both sides cite a range of treaties and international agreements from over the decades to support their conflicting territorial claims.

Erdoğan made the rare move of tweeting in Greek and English, saying: "As Turkey will not resign its rights in the Aegean, it will not hesitate either to make use of its rights arising from international treaties on the issue of the islands' demilitarization."

Greek government spokesperson Giannis Oikonomou commented that Erdoğan's choice of Greek was "notable."

"It is clear to everyone that our country has upgraded its geostrategic and geopolitical footprint as well as its deterrent capacity to be able at any time to defend its national sovereignty and sovereign rights," he said.

Western Thrace

Erdoğan also touched upon the problems of the Turkish minority in Greece's Western Thrace region, he added: "Greece still continues to put pressure on the Turkish minorities in the western Thrace, Rhodes and Kos, ignoring international agreements, universal human rights and the values of the European Union of which it is a member."

Turkey has long decried Greek violations of the rights of its Muslim and Turkish minorities, from closing down mosques and shutting down schools to not letting Muslim Turks elect their own religious leaders.

Under a 2008 European Court of Human Rights (ECtHR) ruling, Western Thracian Turks' right to use the word "Turkish" in the names of associations was guaranteed, but Athens has failed to implement the ruling, effectively banning Turkish identity in the country.

Greece's Western Thrace region is home to a Muslim Turkish community of around 150,000.

NATO, EU as a tool

Turkish leaders have repeatedly stressed that Ankara favors resolving outstanding problems in the region through international law, good neighborly relations, dialogue and negotiations. Instead of opting to solve problems with Ankara through dialogue, Athens has, on several occasions, refused to sit at the negotiation table and opted to rally Brussels to take a tougher stance against Turkey.

Speaking on Greece's efforts to use NATO and other countries as a shield in its moves in the Aegean Sea, the Turkish president said: "Including demilitarized islands in various exercises and seeking to use NATO and third party countries as a tool in this unlawfulness is nothing but an effort that will have a tragic ending."

He went on to say: "As an ally that has paid the highest price within NATO, we have calmly welcomed the provocations of Greece, which has not even responded to our military delegation meeting invitations for the last two years. However, we see that our counterpart misinterprets our patience and calm."