A Turkish military official said the pilot of the jet had been warned by Turkish F16s 10 times in five minutes that its air space had been violated. Russia said the plane appeared to have been fired on from the ground.
Footage from private broadcaster Haberturk TV showed a warplane, believed to be a Russian-made Sukhoi-24, going down in flames in a woodland area, a long plume of smoke trailing behind it.
It went down in area known by Turks as Turkmen Mountain in northern Syria, near the Turkish border, Haberturk said.
Separate footage from Turkey’s Anadolu Agency showed two pilots parachuting out of the jet before it crashed. One of the pilots is reported to be in the hands of Turkmen forces in Syria who are searching for his colleague.
Russia has been carrying out air strikes in Syria in defence of President Bashar al-Assad and against Syrian rebel groups and Islamic State.
Russia’s defence ministry confirmed that the jet was Russian, but said it had not violated Turkish air space.
The ministry said in a statement: “Today on the territory of Syria, supposedly as a result of shooting from the ground, a plane of Russian air force group in Syria, a Sukhoi-24, crashed in the Arab republic of Syria.
“The fate of the pilots is being checked now. According to the first information, both managed to eject.”
Turkey called this week for a UN Security Council meeting to discuss attacks on Turkmens in neighbouring Syria, and last week Ankara summoned the Russian ambassador to protest against the bombing of their villages.
Ankara has traditionally expressed solidarity with Syrian Turkmens, who are Syrians of Turkish descent.