Russia has blamed Israel and threatened retaliation after one of its military planes was shot down by Syrian missiles in a “friendly-fire” incident.
It said Israeli jets attacking targets nearby had “used the Russian plane as a cover, exposing it to fire from Syrian air defences”.
Russia’s defence ministry said the aircraft, carrying 15 servicemen, disappeared from radar 22 miles (35km) off Syria on Monday night as it was returning to Hmeimim airbase, near Lattakia.
It said Israel had not warned it about the jets’ attack until a minute before, and that it reserved “the right to proper retaliatory actions”.
Everyone on board died when the IL-20 reconnaissance plane was hit by one of four surface-to-air missiles, said the defence ministry.
“We view the actions of the Israeli military as hostile,” a spokesman told Russian state television.
“Hiding behind the Russian aircraft, the Israeli pilots put it in the line of fire of Syrian anti-aircraft systems. As a result the IL-20… was shot down by the (Syrian) S-200 missile system,” said Igor Konashenkov.
He said Israeli pilots “could not have failed to see the Russian aircraft, as it was coming in to land from a height of five kilometres (three miles)”.
Israel confirmed it had carried out airstrikes, which it said targeted a facility involved with making weapons that would be used against the country.
It expressed “sorrow” over the deaths but said it held the Assad regime responsible.
“Extensive and inaccurate Syrian anti-aircraft fire caused the Russian plane to be hit and downed,” said a statement from Israel Defense Forces.
It said the jets were back in Israeli airspace when Syria launched the missiles, which it said were fired “indiscriminately” and without checking if Russian planes were in the air.
Syrian officials have so far not commented.
An earlier Russian statement said they had also “detected rocket launches from the French frigate Auvergne”. France denied any involvement in the aircraft’s downing.
Foreign powers backing different sides in Syria’s war often use hotlines to try to ensure they do not accidentally attack each another – but the risk remains high.
Russia’s military has been supporting Syria’s President Bashar al Assad since late 2015, but it has come at a cost with a number of fatal air incidents.
In March 2018, 39 people died when a Russian transport plane crashed while coming in to land at the Hmeimim base; and in December 2016 a TU-154 on its way to Syria crashed, killing 92 people including army musicians and dancers.