A spokesperson for the Russian armed forces told RIA Novosti that the officer was stationed to hunt down crucial Isis facilities and provide co-ordinates for bombing.
“The officer died as a hero, calling a strike on to himself after he was compromised and surrounded by terrorists,” the source said.
Officials said Vadim Kostenko hung himself after falling out with his girlfriend but his relatives insisted he did not kill himself, citing unexplained injuries on his body.
Mr Putin ordered the Russian defence ministry to begin the withdrawal of the “main part” of its military contingent in Syria last week, with fighter jets starting to arrive back in the country the following day.
But American officials said they had seen no significant reduction in Moscow’s combat power, particularly on the ground, as efforts continue to deescalate the civil war and draw up a blueprint for a lasting peace agreement.
In pictures: Russian air strikes in Syria
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The United Nations and humanitarian organisations have raised concern about the death of civilians and opposition fighters Russian air strikes, but the Kremlin insists it has been targeting Isis.
Russian jets are currently supporting troops loyal to Bashar al-Assad, along with allies from Hezbollah and the Iranian Revolutionary Guards, in an advance on the Isis stronghold of Palmyra.
The defence ministry said it launched 41 sorties between Sunday and Wednesday, hitting “more than 320 terrorists” along with tanks, vehicles, artillery positions and ammunition depots.
But while Russian and Syrian media claimed progress was being made after the capture of a castle on the outskirts of Palmyra, other reports said Isis was still in control of the city centre.
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