Greek defence sources said on Sunday the encounter occurred after its jets intercepted Turkish aircraft in what are common but at times dangerous manoeuvres by two NATO allies.

But Turkish foreign ministry spokesman Hami Aksoy denied there had been any "harassment".

"The jets were conducting their routine activities in the Aegean," Aksoy said.

"There is no benefit to this country in trying to escalate tensions by dramatising routine flights," the spokesman said in a statement, as he urged Athens to focus on "confidence-building measures initiated by the two countries' defence ministries".

Greek Defence Minister Nikos Panagiotopoulos and army chief of staff general Konstantinos Floros were on board a helicopter that had taken off from the small island of Inoussses following a visit to forward bases near the border with Turkey.

The Greek foreign ministry had "condemned the harassment", calling on Turkey to respect established rules instead of "systematically violating them".

Relations between the two countries are strained over multiple issues including Ankara's decision earlier this year to re-open its border with Greece for refugees trying to reach Europe.