Turkey said on Thursday it opposed Greece's "unilateral activities" in hydrocarbon fields south of Crete with a consortium led by US oil major Chevron as a violation of international law and good neighbourly relations.
The Chevron-led consortium signed exclusive lease agreements on Monday to look for natural gas off southern Greece, expanding the United States' presence in the eastern Mediterranean.
"We oppose this unlawful activity, which is being attempted in violation of the 2019 Memorandum of Understanding on Maritime Jurisdiction between Libya and our country," the Turkish Defence Ministry said at its weekly press briefing.
It said the activity, while not directly impacting Turkey's continental shelf in the region, also violated Libya's maritime jurisdiction declared to the United Nations on May 27, 2025.
"We continue to provide the necessary support to the Libyan authorities to take action against these unilateral and unlawful activities by Greece."
The 2019 agreement signed by Turkey and Libya set out maritime boundaries in the Mediterranean Sea and was rejected by Greece as it ignored the presence of the Greek island of Crete between the coasts of Turkey and Libya.
The Chevron deal doubles the amount of Greek maritime acreage available for exploration and is the second in months involving a US energy major as the European Union seeks to phase out supplies from Russia and the US seeks to replace them.
Neighbours and NATO members Turkey and Greece have been at odds over a range of issues for decades, primarily maritime boundaries and rights in the Aegean, an area widely believed to hold energy resources and with key implications for airspace and military activity.
A 2023 declaration on friendly relations prompted a thaw in rhetoric between the two countries, though issues have remained unresolved despite leaders voicing a desire to address them.
(Reporting by Tuvan Gumrukcu; Editing by Daren Butler)
