A Turkish frigate sailed on Greek waters, to the south of the island of Kythnos in the early hours of Saturday, according to the Hellenic National Defense General Staff.
The frigate violated Greek waters at the Cyclades, going to the Kafireas straight before heading east again and sail west of Psarra, close to Chios in the eastern Aegean.
The HNDGS said that Navy boats and monitoring systems are discreetly following the course of the Turkish warship.
Originally a pair of aircraft also followed the Turkish frigate.
The warship?s move has additional significance as it comes on the eve of Greece?s national holiday.