Greece’s Prime Minister Kyriakos Mitsotakis has warned Athens will use its EU veto against a European peace proposal unless a maritime agreement between Libya’s Government of National Accord (GNA) and Turkey is shelved. “Greece will veto even at a foreign ministers’ level meeting before it makes it to the head of states level,” Mr Mitsotakis said on Thursday about the potential of a deal between Libya’s two warring factions at an upcoming summit in Berlin. Athens has railed against a maritime border deal between the GNA in Tripoli and Ankara which dramatically expanded Turkish influence in the Mediterranean. In exchange for Turkish military cooperation, Tripoli’s GNA has granted an agreement on sea borders which ignores Athens’ rights to areas thought to contain rich natural gas deposits. Mr Mitsotakis decried the deal as “unacceptable and illegal” in an interview with Greece’s Alpha TV Thursday. He also hit out at the organisers of the Berlin Conference on Libya which is due to be held on Sunday for not inviting Greece to take part. The Greek prime minister’s comments came as the leader of the Libyan National Army (LNA), Field Marshal Khalifa Haftar, arrived in Athens ahead of the talks in Berlin. In images released by Greece’s ministry of foreign affairs, Mr Haftar appeared in discussion with Greek foreign minister Nikos Dendias. Speaking after the meeting, Mr Dendias said the Greek government had encouraged Mr Haftar to work to achieve a cease-fire and restore security in Libya "by removing the mercenaries and by recognition of the non-validity of the illegal agreements between Turkey and the [GNA]." Mr Dendias added Greece was willing to help police a European ban on arms shipments to Libya. Germany and the UN are hoping Libya’s two rival factions will agree to a truce and monitoring arrangements in Berlin this weekend. These provisions are viewed as the first steps to peace in the war-torn country. Mr Haftar and the head of the GNA, Fayez Al Sarraj are both due in Berlin on Sunday - along with representatives from the UAE, Russia, Turkey, Egypt and other Western powers. The UAE's Minister of State for Foreign Affairs, Anwar Gargash, tweeted on Friday that "the UAE unreservedly supports German efforts in convening the conference & the international community's goals of peace & stability in Libya". The minister added that he is "Looking foreword to a successful Berlin Conference" and stressed the joint efforts towards an end to the conflict in Libya.