The Turkish army’s 120 vessels, 50 aerial vehicles and 15,000 personnel from naval, lans and air forces joined the Blue Homeland military exercise, which began on April 3. The exercise, which will conclude on April 9, is being carried out in the Black Sea, Aegean Sea and Eastern Mediterranean. The three areas are under the risk of tensions that occasionally escalate, requiring Türkiye to remain committed to steady defense spending. The Black Sea has seen an increased threat of spillover from the Russia-Ukraine conflict, from stray naval mines and drones washing ashore to attacks on commercial ships near Turkish shores. The Aegean Sea, in the meantime, remains a source of tension with Greece due to maritime jurisdiction disputes.

The Ministry of National Defense said in a statement that the exercise aimed to increase the preparedness level of the army and assessing the capacity of transfer and command in commands under the Naval Forces. The ministry said the exercise will also contribute to development of judgment, foresight and decision-making skills in multi-threat environments for personnel and elements joining the Blue Homeland, as well as trial of interoperability between commands of different forces of the army.

"Blue Homeland" is also the name of a doctrine conceived by two former Turkish naval officers. The doctrine encompasses Türkiye’s maritime jurisdictions, exclusive economic zone and continental shelf in line with United Nations resolutions. These connected issues have been a source of dispute between Türkiye and Greece for decades.

Ankara and Athens seek to improve relations after years of hostilities but maritime jurisdictions remain a thorny issue. The countries that came close to an all-out war in the 1990s over the Aegean Sea remain vigilant, with Türkiye concentrating on developing a domestic defense industry. Greece relies on foreign partners to boost its defenses.

The exercise had been on a two-year hiatus before Türkiye decided to resume in January 2025.

Embracing the doctrine of being effective and powerful at sea as its predecessor the Ottomans were once, Türkiye in the past two decades has developed an independent defense industry capable of operating in open waters, thereby shifting geopolitical balances in its favor. The navy plays a critical role in ensuring the security of maritime trade routes in the Eastern Mediterranean, the Black Sea and the Aegean Sea, promoting regional stability. In the past two decades, Türkiye has reached a milestone by designing and producing its own warships. The TCG Heybeliada, the first indigenous corvette, was commissioned in 2011, followed by projects for indigenous frigates and destroyers. The ADVENT combat management system, developed domestically, represents a significant achievement, enhancing the capabilities of the Turkish navy. In 2024, the country commissioned its first of six planned Reis-class submarines. The project for the Piri Reis submarine, the first of its class, was launched in 2019. It has a length of 68.35 meters (224.25 feet) and a capacity of 40 personnel.

Though they bolstered their defenses, Türkiye and Greece still count on a full thaw in relations. After a long period of tensions marked by disputes over irregular migration, the Cyprus dispute, energy exploration and territorial sovereignty in the Aegean, the two countries have been taking confidence-building steps, which moved into a new chapter with President Recep Tayyip Erdoğan’s landmark visit to Athens two years ago.

While officials on both sides have expressed commitment to maintaining the positive climate, the issues are longstanding and deep-rooted, and neither side expects the process to be without turbulence, particularly in the Aegean, where Turkish and Greek jets often scuffled until very recently.

Ankara has repeatedly warned its neighbor against entering an arms race with Türkiye, particularly on building a military presence on the disputed Aegean islands since the 1960s, in violation of postwar treaties.

Türkiye’s Defense Ministry on March 12 accused Greece of violating international treaties governing the status of several Aegean islands, warning that Athens’ recent initiatives undermine bilateral relations and contradict the legal framework established by international agreements.

Speaking at the ministry’s weekly press briefing in Ankara, Defense Ministry spokesperson Zeki Aktürk said Greek actions regarding the islands run counter to provisions set out in the 1923 Treaty of Lausanne and the 1947 Paris Peace Treaty, which require certain islands to remain demilitarized.

"The initiatives by Greece that violate the status of the islands contrary to duly concluded treaties both create legal violations and damage our neighborly and allied relations,” Aktürk said.

He noted that the Eastern Aegean islands were transferred to Greece under the Lausanne Treaty and the Paris Peace Treaty on the condition that they remain demilitarized.

According to the ministry, islands including Limnos and Karpathos fall under provisions that require them to maintain a demilitarized status.

The ministry said any actions that alter this status constitute a breach of the agreements and stressed that unilateral steps cannot legally terminate the demilitarized provisions established by international treaties.

"These fait accompli attempts do not lead to the unilateral termination of the demilitarized status,” the ministry said in a statement.

Turkish officials also accused Greece of attempting to use regional tensions to advance its own positions.

"We do not accept Greece’s initiatives that do not serve a genuine purpose and aim to turn the crises in our region into opportunities,” the ministry said, adding that Ankara has taken the necessary measures in response.

It was previously stated that Greece aims to deploy five different types of missile systems on Aegean islands and near the Turkish-Greek land border under the "Achilles’ Shield" project.

The ministry also stressed that disputes between NATO allies are particularly concerning at a time when multiple security crises continue to affect the broader region.