(Bloomberg) -- Russia’s Defense Ministry warned it may respond to “hostile” actions by Israel after a one of its military reconnaissance planes was downed mistakenly by Syrian forces fighting off an attack by Israeli warplanes.

All 15 people aboard the plane died late Monday, according to a ministry statement reported by state news services RIA Novosti and Tass. Israeli forces didn’t provide any warning of their attack, it said.

Four Israeli warplanes were striking targets in the Syrian province of Latakia when the Il-20 plane went off the radar about 35 kilometers (21 miles) from the Mediterranean coast as it returned to base, according to the ministry.

In November 2015, Turkey shot down a Russian warplane on the Syrian border, killing the pilot and prompting Russian economic retaliation and months of diplomatic tensions. Israel regularly attacks Iranian-backed targets inside Syria, with Russia usually refraining from any action.

A U.S. official said earlier that the Russian plane was inadvertently shot down by Syrian anti-aircraft artillery while trying to stop a barrage of Israeli missiles, CNN reported.

An Israel Defense Forces spokesman declined to comment on the reports.

Russia intervened militarily in Syria in 2015 to shore up the regime of President Bashar al-Assad. He has managed with the help of Russia and Iran to re-establish control over two-thirds of the country, though U.S.-backed Kurdish forces hold a major pocket of territory in the northeast and a rebel bastion is holding out in the northwestern province of Idlib.

More on Syria: Putin Yields to Erdogan and Puts Syria Military Advance on Hold

Russia in March suffered the worst official loss of its military campaign in Syria when an An-26 military transport plane crashed as it was landing at the Khmeimim air base, killing all 32 people aboard. Officials said it was a malfunction. U.S. forces in February killed about 200 Russian mercenaries who attacked a base held by mainly Kurdish forces, though Russia denied any involvement in that incident.

To contact the reporter on this story: Henry Meyer in Moscow at hmeyer4@bloomberg.net

To contact the editors responsible for this story: Gregory L. White at gwhite64@bloomberg.net, Lin Noueihed

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