The helicopter was believed to be carrying five people
A Russian helicopter carrying three crew and two officers has been shot down in northern Syria, according to the defence ministry.
The Mi-8 transport helicopter was returning to Khmeimim base in Idlib province after delivering humanitarian aid to Aleppo when it came under attack from the ground on Monday, the ministry said.
All five people in the aircraft were killed, according to the Kremlin.
Images shared on social media apparently showed a dead body stripped of clothes and Russian identity documents taken from the helicopter, Reuters reported.
Kremlin spokesman Dmitry Peskov said the helicopter had tried to veer away from populated areas to avoid civilian casualties and said the service personnel died a "heroic death".
He added that Moscow would continue to fight international terrorism "on all fronts", despite threats from Islamic State.
Rebel groups are staging an offensive to break a government siege on rebel-held parts of Aleppo around 25 miles from the reported crash site.
Pro-Syrian government forces on the ground are being supported by heavy air strikes in the same area
On Sunday, IS posted a nine-minute video to YouTube calling on its members to carry out jihad in Russia.
An Mi-28N helicopter gunship crashed near Homs in April, killing both crew members. The Russian military said there was no evidence it had come under fire.
Some 18 Russian service personnel have been killed since Moscow began airstrikes in Syria in September last year.