BEIRUT, Sept 18, (Agencies): Syria accidentally shot down a Russian military aircraft, killing all 15 crew members, when its air defences swung into action against an Israeli missile strike, Russian and Israeli forces said Tuesday. The incident late Monday was the worst case of friendly fire between the two allies since Russia’s game-changing military intervention in September 2015.The Russian Ilyushin dropped off the radar over the Mediterranean moments after Turkey and Russia announced a deal that offered millions of people reprieve from a threatened military assault in northern Syria.There was no immediate word from Damascus, but the deadly air war sequence started when Israeli missiles struck the coastal region of Latakia on Monday. Israel confirmed that it had targeted a Syrian military facility where weapons manufacturing systems were “about to be transferred on behalf of Iran” to Lebanese Shiite group Hezbollah. It expressed “sorrow” for the Russian deaths, but insisted the Russian plane had been felled by “extensive and inaccurate Syrian anti-aircraft (surface-toair missile) fire”.