ATHENS, Greece (AP) — The commander of forces fighting the U.N.-supported government in war-torn Libya has begun meetings in Athens in a bid to counter Turkey's support for his opponents.

Libyan Gen. Khalifa Hifter met with Greek Foreign Minister Nikos Dendias after arriving for a previously unannounced visit late Thursday. He will continue meetings with Prime Minister Kyriakos Mitsotakis on Friday as well as with other senior Greek officials.

The surprise visit by Hifter takes place ahead of a weekend summit in Berlin aimed at halting the conflict in oil-rich Libya which is being fueled by competing international support for the warring sides.

Turkey, which has promised to send troops to back Libya's government against Hifter's offensive, is at odds with Greece over oil-and-gas drilling rights in the East Mediterranean.

Police maintained a heavy security presence outside the hotel next to parliament in central Athens where Hifter is staying.