Eyewitnesses of the Mi-8 helicopter crash in the Krasnoyarsk area published videos of the crash site.
The Mi-8, operated by the airline UTair, collided near the Vankor oil field with cargo suspened from another helicopter, causing it to crash and explode upon impact.
The helicopter was carrying three crew and 15 oil workers from Vankor No1 oil pumping station in the Krasnoyarsk region. There were no survivors.
Rosaviatsiya confirmed that preliminary data indicated that the passenger helicopter crashed into another aircraft's cargo, although it is unclear yet why.
An investigation is underway.
The Mi-8 has been in constant production since 1967 and is the world's most-produced transport helicopter; thousands of them have been produced and they have been supplied to more than 100 countries throughout the world.