ISTANBUL (AP) — Greece’s prime minister met with Turkey's president over lunch in Istanbul on Sunday in a rare meeting between the neighbors who have been at odds over maritime and energy issues, the status of Aegean islands and migration.

Prime Minister Kyriakos Mitsotakis and Turkish President Recep Tayyip Erdogan were expected to discuss bilateral and international relations as well as Russia's invasion of Ukraine, the Turkish presidency’s communications directorate said.

Greece and Turkey are nominal NATO allies but have strained relations over competing maritito reflect the two leaders metme boundary claims that affect energy exploration rights in the eastern Mediterranean. Tensions flared in the summer of 2020 over exploratory drilling rights in areas in the Mediterranean where Greece and Cyprus claim their own exclusive economic zone, leading to a naval standoff. Turkey also claims Greece is violating international agreements by militarizing islands in the Aegean Sea.

Since then, Greece has embarked on a major military modernization program. Officials from both countries resumed exploratory talks in 2021 after a five-year pause to lay the groundwork for formal negotiations to begin but haven't made much progress.

Greece has also accused Turkey of allowing migrants to cross its land and sea borders despite a deal with the European Union to prevent illegal crossings, while Turkey and rights groups have documented Greek authorities’ practice of migrant “pushbacks” to Turkey.

But the two countries also cooperate on energy projects, including a newly built pipeline that spans their countries transporting natural gas from Azerbaijan to Western Europe ‒ a project that is part of Europe’s effort to reduce dependence on Russian energy exports.

Mitsotakis kicked off his visit by attending a service for Orthodox Christians at the Ecumenical Patriarchate of Constantinople.