Prime Minister Kyriakos Mitsotakis on Monday discussed irregular migration and offshore exploration rights with the son of the de facto leader of eastern Libya during talks in Athens.

Greek officials said the meeting with Saddam Haftar, Deputy Commander-in-Chief of the Libyan Arab Armed Forces, “reconfirmed the historic ties between Greece and Libya” and looked into ways of boosting relations particularly in the fields of the economy and investments.

Athens is at odds with Libya over undersea oil and gas exploration and exploitation rights in the Mediterranean Sea south of Crete, while the north African country has signed a deal with Turkey on the issue that bypasses Greece.

Greek officials are also seeking better cooperation from Libya in stopping a major flow of illegal migration from eastern Libya to Crete that has seen several thousand arrivals so far this year.

Officials said that both issues were on the agenda in Monday’s meeting, but didn’t provide details.