The incident is said to have happened 22km away from the Greek island of Lemnos
A Russian warship has been forced to fire warning shots at a Turkish vessel to avoid a collision, officials have claimed.
The Defence Ministry in Moscow has alleged that the unnamed Turkish ship failed to respond to warnings issued by the Smetlivy navy destroyer in the Aegean Sea.
In a statement, it said the warship had been unable to establish radio contact with the approaching seiner, while visual signals and flares also went unacknowledged.
According to the Interfax news agency, the Turkish fishing vessel sharply changed course after the warning shots were fired - and ended up passing within 500 metres of the Russian warship.
Ankara's military attache has been summoned over the incident, which unfolded 14 miles (22km) away from the Greek island of Lemnos.
It follows a diplomatic stand-off between the two countries, with Vladimir Putin claiming Turkey shot down a Russian warplane to protect oil supplies arriving from Islamic State territory.
The Russian President has described that incident as a "huge mistake", with the Kremlin adamant that the downed jet was in Syrian airspace at the time.
However, Turkey has claimed the warplane had encroached on its territory, despite repeated warnings not to do so.
Mr Putin has called for a series of sanctions to be implemented against Turkey, and Russian tourists are now being urged not to travel there for a holiday. Fruit and vegetable imports have also been banned.