Egypt and Greece on Thursday signed an agreement defining their exclusive economic zones, furthering their ambitions to harvest huge natural gas reserves with Cyprus and Israel, and to further isolate Turkey. The agreement, announced in Cairo after talks between the Egyptian and Greek foreign ministers, could increase tension in the eastern Mediterranean by complicating Turkey’s plans to exploit the gas reserves. Egypt on Sunday protested strongly against a seismic survey by Turkey, saying the work breached its exclusive economic zone. Relations between the two nations have been fraught, with Cairo accusing Ankara of supporting militant groups in the region. They support rival sides in the conflict in Libya. Tension between Greece and Turkey has also been on the rise in recent weeks. It flared up last month over the two Nato members’ long-standing border dispute in the east Mediterranean and the Aegean seas. Ankara announced plans to send a research vessel south of the Greek islands of Rhodes, Karpathos and Kasterellorizo. On Thursday, Egyptian Foreign Minister Sameh Shoukry said the agreement reflected the “political will” of Cairo and Athens to strengthen their relations. “The agreement allows the two nations to exploit their marine wealth in view of the large oil and natural gas reserves,” Mr Shoukry said. The Greek Foreign Minister, Nikos Dendias, said the agreement was the opposite of the marine demarcation pact between Turkey and the Libyan government in Tripoli, which his country and Egypt have dismissed as illegal. Mr Dendias said the agreement between Greece and Egypt would contribute to the stability of the region. He said the accord between Tripoli and Ankara was “void” and “worthless.” Ankara’s maritime agreement with Tripoli significantly expanded Turkey’s continental shelf. This infringed on Egypt’s ambitious plans with Cyprus, Greece and Israel to turn the region into a global energy centre after the discovery of natural gas in enormous quantities. Turkey has been unhappy that it was left out of these plans and has been trying to force itself in. It has explored for gas off the shores of Cyprus, of which Turkey has occupied a third since 1974 when it invaded after a short-lived, Greek-inspired coup. The EU imposed sanctions on Turkey for drilling for gas in water off Cyprus, which is a member of the bloc.