Turkey has formally protested against a new deal which plans to build an underwater electricity cable connecting Cyprus, Greece and Israel.
Ankara has argued that the planned route of the cable passes through Turkish territorial waters.
Turkish officials have presented diplomatic protest notes to Greek, Israeli and EU diplomats in Ankara, stating that the three countries needed to seek Turkey's permission.
Last week, government ministers reached an agreement to approve conduct feasibility studies to build a 2,000-megawatt undersea electricity cable at a maximum depth of 2,700 metres.
Cyprus, Greece and Israel also agreed to coordinate with their respective national electricity regulators on how best to proceed with the plans.
The project to implement the world's longest submarine electricity cable, over a thousand kilometres long, is expected to be funded by the European Union.
But Turkey has demanded that it must approve any work carried out on their claimed continental shelf.
According to the Turkish press, Ankara's move was in response to an agreement signed on March 8 between Cyprus, Greece and Israel.
The issuing of "diplomatic notes" comes as Greece and Turkey resume talks to try to settle their dispute over gas exploration in the eastern Mediterranean.
Despite EU warnings, Ankara has sent the seismic research vessel Oruç Reis to disputed waters claimed by Greece and also ordered drilling ships into an area where Cyprus claims exclusive rights.
The tension provoked the worst diplomatic crisis since 1996 and brought the two NATO allies close to open conflict last year, but tensions have eased since then.
Turkey is relying on a maritime delimitation agreement signed in November 2019 with the Tripoli-based Libyan government to claim a vastly expanded continental shelf in the Mediterranean
Meanwhile Israel, Cyprus and Greece had previously signed up for a planned underwater pipeline, intended to carry gas from new offshore deposits to continental Europe, bypassing Turkey.
Cyprus, Greece, and Israel also conducted a joint naval exercise last week, in the latest example of increased cooperation between the countries.