Turkey has challenged seabed surveys for an undersea electricity cable linking Greece and Cyprus, claiming that a French-flagged research vessel requires Ankara's formal approval. The diplomatic dispute centres on the Great Sea Interconnector project, where competing maritime boundary claims in the Eastern Mediterranean continue to create friction.
The Turkish Ministry of Foreign Affairs stated that planned survey activities by the French vessel Abeille Marengo are illegal, arguing that portions of the survey route lie within Turkey's continental shelf. Ankara claimed that the required consent process under international maritime law has not been completed, while framing ongoing discussions with Paris as an effort to obtain Turkish approval.
Turkish officials acted hours after Greece finalised its domestic licensing procedures and issued a formal navigational telex, known as a NAVTEX, authorising the survey ship to begin seabed work. Ankara quickly issued a counter-notice, reiterating its longstanding maritime claims and disputing the validity of Greek and Cypriot authorisations.
Turkish diplomatic protest and counter-notice
In an official statement on unauthorized marine scientific research, the Turkish foreign ministry claimed that the French-flagged vessel intends to carry out illegal research and lay underwater cables without permission. Ankara said the vessel's planned path infringes upon the outer limits of the continental shelf that Turkey submitted to the United Nations on March 18, 2020.
The Turkish ministry asserted that navigational advisories issued by Greece and the Republic of Cyprus had been cancelled by Turkey. While insisting that Ankara remains resolute in protecting its sovereign rights under international law, the statement added that Turkey would continue to pursue an approach based on cooperation, dialogue, and coordination across the region.
Turkey set out its maritime objections through naval warning TURNHOS 1105/26 for the Mediterranean Sea, which directly challenged Greek advisory HA15-1411/26. The message stated that part of the designated area lies within the Turkish continental shelf registered in United Nations document A/74/757. It noted that Turkish authorities had not granted consent, ordered that all research activities in Turkish maritime jurisdiction areas must be coordinated with Ankara, and fixed an expiry date of March 6, 2027, at 22:00 UTC.
Greek diplomatic sources firmly rejected the Turkish intervention, stating that operations by the French research vessel VB Abeille Marengo will advance according to the contractor's operational schedule. Greek officials emphasised that the vessel will operate strictly within Greek and Cypriot territorial waters and continental shelf areas, adding that international law of the sea is clear and leaves no room for alternative interpretations.
Greek licensing and seabed survey permits
The latest diplomatic exchange follows an official announcement from the Greek Ministry of Foreign Affairs confirming the completion of regulatory procedures for seabed research and cable installation. The permits were requested by French cable manufacturing company Nexans on behalf of project developer Great Sea Interconnector.
Greek Foreign Minister Giorgos Gerapetritis issued the formal licensing decision on November 6, 2026, following a positive recommendation by the Interministerial Committee for Granting Marine Research Licences, known as EXAETH. The research vessel then requested the required navigational warning, which the Hellenic Navy Hydrographic Service issued immediately.
Authorities in Cyprus mirrored the Greek measures, with the maritime station at Larnaca issuing a corresponding NAVTEX for research by the VB Abeille Marengo within the Cypriot exclusive economic zone. The coordinated notices clear the ship to gather seabed data along the planned route between Crete and Cyprus.
Greece's Independent Power Transmission Operator, known as ADMIE, and Great Sea Interconnector announced that the joint Greek and Cypriot navigational advisories will allow the Abeille Marengo to conduct technical seabed surveys. The companies explained that the research forms part of ongoing technical development and will provide critical data needed for the detailed engineering design of the interconnection.
Bilateral coordination between Athens and Nicosia
Diplomatic preparations included direct ministerial communication, with Greek Foreign Minister Giorgos Gerapetritis holding a telephone call with Cypriot Foreign Minister Konstantinos Kombos on November 6 to ensure close coordination between Athens and Nicosia. The Greek foreign ministry reported the discussion in an official post on social media platform X.
Research vessel operations and regional tensions
The French-flagged Abeille Marengo has been stationed at the port of Heraklion on Crete, waiting for operational signals to establish its survey areas and timetable. Operations are focused on waters east of Crete and the island of Kasos, the same maritime area where seabed surveys were interrupted during the summer of 2024 because of naval tensions between Greece and Turkey.
Greek officials have maintained that there will be no retreat and that the cable initiative, which operates under French corporate and diplomatic involvement, will proceed as scheduled. Athens has analysed potential response scenarios in the event of new challenges from Ankara, but Greek authorities expect that high-level dialogue between Paris and Ankara, along with backing from Brussels, will prevent a repeat of the maritime confrontations seen in 2024.
Greek political resolve and European backing
Greek Prime Minister Kyriakos Mitsotakis addressed maritime tensions days earlier before the United Nations Security Council, warning that an agreement between Turkey and Libya could be used as a pretext to contest lawful maritime operations or hinder strategic connectivity. Mitsotakis said such connectivity projects provide immense strategic and economic benefits, including cheaper electricity, enhanced energy security, better digital links, and greater regional cooperation, while insisting that arbitrary maritime claims cannot be allowed to block regional development.
Greek government spokesman Pavlos Marinakis reiterated that stance during an interview on Skai television, confirming that licensing procedures have been carried out exclusively by Greek authorities. Marinakis stated that the timetable announced by the foreign ministry and relevant departments will be observed without delay, and that all permit applications had been submitted directly to Greek officials.
Marinakis stressed that the project extends far beyond Greek national interests, describing it as a wider European undertaking involving Greece, Cyprus, France, and the European Union. He affirmed that Greece will not step back from a strategic energy project designed to end the energy isolation of Cyprus.
Strategic role of the Great Sea Interconnector
The Great Sea Interconnector project entails laying an undersea high-voltage electricity cable spanning approximately 900 kilometres between Crete and Cyprus, with an initial transmission capacity of 1,000 megawatts. The infrastructure aims to integrate Cyprus into the European power grid, ending its status as the only European Union member state entirely disconnected from continental electricity networks.
The subsea cable will enable Cyprus to import power when domestic generation costs are uncompetitive and export surplus electricity during periods of high generation from renewable sources, particularly solar parks. In addition to strengthening security of supply and supporting clean energy investment, the project bolsters Greece's strategic ambition to establish itself as a central energy hub across the Southeastern Mediterranean.
