The Republic of Cyprus has lodged a formal complaint with the United Nations over what it describes as illegal research activities carried out by the Turkish-flagged research vessel Akdeniz Arastirma 1 in the maritime zones of Cyprus. The move is particularly significant given that surveys for the Great Sea Interconnector (GSI) electricity cable project are expected to resume in the coming period, with the route extending into Cypriot waters.

Although the letter (A/81/413) concerns marine scientific research, which is theoretically governed by a different legal framework from surveys related to cable-laying, it sets out virtually the entire legal argument against what Nicosia regards as Ankara’s unlawful activities in the maritime zones of third countries, whether these involve areas under their sovereignty and sovereign rights or areas in which they exercise jurisdiction.

According to the letter submitted by Cyprus’s Permanent Representative to the United Nations, Maria Michael, the vessel’s unauthorised entry into the territorial waters of the Republic of Cyprus and its conduct of marine scientific research there without the Republic’s express consent constitute a violation of Cypriot sovereignty, as enshrined in Articles 2 and 3 of the United Nations Convention on the Law of the Sea (UNCLOS).

The letter also stresses that, in exercising its sovereignty, the Republic of Cyprus has the exclusive right under Article 245 of the Convention to regulate, authorise and conduct marine scientific research in its territorial waters.

It further argues that conducting marine scientific research within Cyprus’s exclusive economic zone (EEZ) and continental shelf, where the Republic exercises jurisdiction over such activities, constitutes an additional violation of UNCLOS. Article 56(1) of the Convention, it notes, grants the coastal state exclusive jurisdiction over marine scientific research within its EEZ.

Furthermore, under Article 246(2) of the Convention, marine scientific research in an exclusive economic zone and on a continental shelf may be conducted only with the consent of the coastal state. In the case of the Turkish research vessel, the Republic of Cyprus has not granted such consent.

In its letter to the UN, Nicosia calls on the organisation to convey a clear message to Turkey that it must fully comply with its obligations under international law, respect the sovereignty and jurisdiction of the Republic of Cyprus, and refrain from conducting marine scientific research in Cypriot maritime zones without its consent, claiming to have authorisation for such activities or facilitating them.

The full letter from the Republic of Cyprus

Acting on the instructions of my Government, I wish to draw your attention to illegal actions by the Republic of Türkiye involving marine scientific research activities conducted by the Turkish-flagged research vessel Akdeniz Arastirma 1 in the maritime zones of the Republic of Cyprus.

Specifically, between 15 and 30 June 2026 and between 3 and 29 August 2026, the aforementioned vessel carried out water-sampling operations in the maritime area between Cyprus and Türkiye, including areas within the territorial waters and exclusive economic zone (EEZ) of the Republic of Cyprus, without the consent of the Republic of Cyprus. The relevant maps are attached as Annexes I and II, respectively.

The unauthorised entry of the vessel into the territorial waters of the Republic of Cyprus and the conduct of marine scientific research within them without the express consent of the Republic of Cyprus constitute a violation of the sovereignty of the Republic of Cyprus, as enshrined in Articles 2 and 3 of the United Nations Convention on the Law of the Sea.

In exercising its sovereignty, the Republic of Cyprus has, under Article 245 of the Convention, the exclusive right to regulate, authorise and conduct marine scientific research in its territorial waters. These provisions reflect customary international law.

Furthermore, the conduct of marine scientific research within the exclusive economic zone and on the continental shelf, where the Republic of Cyprus exercises jurisdiction over such activities, constitutes a further violation of the United Nations Convention on the Law of the Sea.

Article 56, paragraph 1(b)(ii), of the Convention grants the coastal state exclusive jurisdiction over marine scientific research within its exclusive economic zone. Furthermore, under Article 246, paragraph 2, of the Convention, marine scientific research in the exclusive economic zone and on the continental shelf may be conducted only with the consent of the coastal state. No such consent was requested from or granted by the Republic of Cyprus.

Accordingly, Türkiye has absolutely no legal basis for undertaking, claiming to authorise or facilitating marine scientific research activities within the maritime zones of the Republic of Cyprus without its consent.

In light of the above, my Government respectfully requests your assistance in conveying a clear message to Türkiye that it must fully comply with its obligations under international law, respect the sovereignty and jurisdiction of the Republic of Cyprus, and refrain from conducting, claiming to authorise or facilitating marine scientific research activities within the maritime zones of the Republic of Cyprus without its consent.

I would be grateful if this letter and its annexes could be circulated as a document of the General Assembly under agenda items 39 and 74, and published on the website of the Division for Ocean Affairs and the Law of the Sea, as well as in the next edition of the Law of the Sea Bulletin.