Greek government spokesman Dimitris Tzanakopoulos said on Monday that there was no evidence of any "violation of Greek territory" following claims by Turkish Prime Minister Binali Yildirim that the Turkish coast guard took down Greek flag from an Aegean islet.
Yildirim had indicated that the islet was in a "disputed area" in the Aegean, a concept that Greece rejects.
"Based on the latest briefings from the Defense Ministry and the Hellenic Navy General Staff, there is no confirmation of any incident of violation of Greek territory," Tzanakopoulos told reporters.
"Nonetheless we continue to investigate the matter in a calm and very serious fashion."
Yildirim's statement is "totally provocative and reprehensible," Tzanakopoulos added. "Greece will never accept the theory of 'gray zones' or any questioning of its territorial sovereignty."
"I think Mr Yildirim should be more careful," Tzanakopoulos said. "We call on Turkey to return to a path of respect for international law," he said, adding that Turkish authorities should "take the initiative to deescalate the tension."