A Russian military helicopter carrying five people was shot down in the north of Syria's rebel-held Idlib province on Monday, the Russian defence ministry said.
Russian air forces are supporting President Bashar al-Assad in Syria's five-year-old civil war.
Images shared on social media purportedly showed a dead body stripped of his clothes and Russian identity documents taken from the crashed helicopter.
The defence ministry said it was an Mi-8 military transport helicopter which had been shot down after delivering humanitarian aid to the city of Aleppo as it made its way back to Russia's main air base in the western province of Latakia.
Around 40 km north-east of the crash site, rebel groups are staging an offensive to break a government siege on rebel-held parts of eastern Aleppo city.
Pro-government forces on the ground are being supported by heavy air strikes in the area.
Russia's defence ministry said the helicopter was carrying two officers and three crew members.
Men inspect the wreckage of a Russian helicopter that had been shot down in the north of Syria's rebel-held Idlib province, Syria August 1, 2016.