A Russian fighter jet was shot down Tuesday over the Turkish-Syrian border, the Defence Ministry in Moscow said, according to Interfax news agency.
The Sukhoi Su-24 was reportedly downed by Turkish forces, Turkish state news agency Anadolu reported, citing sources in the presidency.
The report said that the jet violated Turkish airspace and ignored warnings.
It crashed in the north-western Syrian town of Bayirbucak, Turkish security sources were quoted as saying.
A monitoring group, the Syrian Observatory for Human Rights, said: "A plane - we do not know if it's Russian or Syrian - was seen in flames in the sky over the Turkmen mountains near the Syrian-Turkish border."
Activists in the area posted a video online showing the plane crashing and someone screaming: "God is great it is a Russian plane." The footage could not be independently verified.
The area near the crash site, in the northern outskirts of the coastal city of Latakia, witnessed fierce clashes and airstrikes, activists said.
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