Turkish coast guard units staved off Greek coast guard patrol boat, which harassed Turkish fishing boats with warning shots at Aegean Sea, the Coast Guard Command said Thursday.

The incident took place near the Didim district in Aydın province, where Greek coast guard units attempted to harass a Turkish fishing boat at 12.02 p.m. local time (9 a.m. GMT). A coast guard boat immediately arrived at the scene upon the call of the fishing boat and pushed the Greek coast guard away.

The Turkish coast guard retaliated in kind after the Greek side fired warning shots as they left the area, the statement said.

The two neighbors and NATO allies are at odds over a number of issues such as competing claims over territorial waters in the Aegean Sea and jurisdiction in the Eastern Mediterranean, air space, energy, the ethnically split island of Cyprus and the status of islands in the Aegean.

Offshore exclusive economic zones are maritime areas agreed on between neighboring states, defining where a country has commercial rights such as the right to explore for hydrocarbons. Those zones can extend to up to 200 nautical miles from a shoreline, or, if sharing the sea area with another state, the equidistance between the two.

But in the case of Greece and Turkey, the issue is complicated by disputes over the extent of their continental shelves and the limit of their territorial waters. The dispute has held up any declaration by Greece to extend its territorial waters to 12 miles from 6 miles in the Aegean.