Turkey has warned that a French ship preparing to survey the route of an undersea power cable between Greece and Cyprus would be operating on its continental shelf without permission.
But it also said talks over the work were "not yet completed," a signal that NATO allies Greece and Turkey may avoid another naval standoff in the eastern Mediterranean.
The stakes go well beyond the cable.
The Great Sea Interconnector, backed by the European Union, would end the island nation of Cyprus' isolation as the only EU member not linked to Europe's power grid. It is also a test of whether Athens and Ankara, whose maritime disputes have repeatedly brought their navies close to confrontation, can manage a major infrastructure project without a crisis.
Work stalled in the summer of 2024, after Turkish warships appeared near the Greek island of Kasos and survey operations were halted.
Hours before Turkey's statement, Greece said it had completed licensing for the French company Nexans and issued a maritime safety notice for its cable-laying ship, the Abeille Marengo, valid until March 2027.
Turkey responded with a counter-notice and a Foreign Ministry statement calling the work "unauthorized marine scientific research."
It said part of the area lies within maritime boundaries it declared unilaterally to the United Nations in 2020, and claimed to have "canceled" the Greek and Cypriot notices. Still, the ministry ended by pledging "cooperation, dialogue and coordination."
France has stepped in as an intermediary, notifying Ankara about the work so Athens is not seen asking Turkey for permission.
The dispute now turns on the wording of that French notice. Greece insists it can only be a routine safety notification that recognizes no Turkish claim. Turkey is presenting it as a request for its consent.
The distinction matters: accepting any consent process could set a precedent for later phases of the project.
The ship is expected to start in Greek territorial waters.
The real test will come off Kasos, where the work stopped two years ago.
By Antonis Telopoulos