This morning between 12:30 and 13:00 CET an unidentified aircraft entered into Athens FIR ( Flight Information Region) off island of Limnos to exit south of the island of Chios.
The aircraft, probably a Turkish plane, entered an invalid trasponder code and flew at 27k feet (speed between 500 and 600kts) over central Ageagn Sea before to came back into Istanbul FIR.
There are hundreds of violations of the Athens FIR by Turkish aircraft reported by the Hellenic Air Force every year.