In a major international incident, it is said that a Russian military jet carrying 14 servicemen vanished from radar over the Mediterranean Sea.
The incident apparently happened late Monday.
It is said that at the time, Syria came under attack by Israeli missiles.
The Russian Defence Ministry said that connection with the military jet has been lost over the Mediterranean Sea 35 kilometres from the Syrian coast.
The Russian side is keen and eager to ascertain the fate of military jet and have initiated a massive search operation.
The ministry said that the jet had gone off the radar around 11pm Monday (2000 GMT) during an attack by four Israeli F-16 jets over Syrian infrastructure.
The Israeli attack came in on the province of Latakia, which is considered a stronghold of President Bashar al-Assad.
Pentagon has so far clarified that it was not involved in the incident in any way.
Russia-backed forces of the Syrian regime have massed around Idlib province in recent weeks, sparking fears of an imminent air and ground attack to retake the last major opposition bastion.>