The rebel Free Syrian Army (FSA) says it has shot down a military aircraft near the Iraqi border.
The FSA says the aircraft was shot down near the town of al-Muhassan, about 120km from the Iraqi border in Deir al-Zour province. It says that one of the two-man crew died and that another has been captured.
A group calling itself the "Revolutionary Youth of the Land of the Euphrates" uploaded a video to YouTube purporting to show the captured pilot surrounded by three armed rebels, saying that his mission was to "bomb the town of al-Muhassan".
In the video, which cannot be independently verified, the seemingly middle-aged man identifies himself as a pilot, Colonel Fareer Mohammad Suleiman. He appears to have minor bruising to his face which he attributes to the plane crash.
In other footage provided by the rebels, what appears to be a Russian-built MiG-23 fighter jet is shown carrying two under-wing weapons pods thought to be loaded with air-to-ground missiles.
Anti-aircraft fire can be heard before the jet bursts into flames.
According to Syria's state-run news agency Sana, however, the plane that went down had suffered a fault with its control mechanisms during a routine training mission, forcing the pilot to abandon the aircraft.
The BBC's correspondent in neighbouring Lebanon says that if the rebels have succeeded in downing a MiG-23, it would be a significant moment in the conflict.