The US military believes that Syrian anti-aircraft artillery accidentally shot down a Russian maritime patrol aircraft Monday while the Syrian regime was attempting to shoot down a barrage of Israeli missiles targeting locations in Latakia, a US official tells CNN

https://twitter.com/rabrowne75/status/1041829666565308416

UPD1 CNN: Syrian regime accidentally shoots down Russian military plane

UPD2 The Russian Ministry of Defence (MoD) confirmed that the Russian Air Force Il-20 surveillance aircraft which went missing over the Mediterranean Sea was downed by Syrian air defense system blaming Israel for “triggering a chain of events that led” to the incident.

The Times of Israel: In rare move, IDF admits Syria strike, expresses sorrow over Russian plane