Turkey warned of consequences on Saturday after saying a Russian SU-34 jet had violated its airspace despite warnings, once more stoking tensions between two countries involved in Syria's war, but Russia denied that there had been any incursion.
In a similar incident in November, Turkey shot down a Russian warplane flying a sortie over Syria that it said had violated its airspace, triggering a diplomatic rupture in which Russia imposed economic sanctions.
Russian Defence Ministry spokesman Major-General Igor Konashenkov denied that any Russian plane had entered Turkish airspace, and called the Turkish allegation "pure propaganda".
He said Turkish radar installations were not capable of identifying a particular aircraft or its type or nationality, and that no verbal warning had been issued in either English or Russian.
Turkey's Foreign Ministry said in its statement that the Russian ambassador had been summoned late on Friday, and that the violation was a clear sign that Russia wanted issues between the two countries to escalate.