Nineteen people died on Friday after a helicopter transporting oil and gas workers crashed in Siberia.
According to the BBC, a Mi-8 helicopter crashed in northwestern Siberia while transporting 22 people in the Yamalo-Nenetsky region.
Aviation officials told the Guardian that 16 of the 19 passengers abroad the helicopter and all three crew members died.
Most of the people on board the aircraft were oil and gas workers.
According to the TASS news agency, the oil and gas workers aboard the aircraft were employed by a contractor working for Russia’s Rosneft.
The helicopter was transporting workers from an oil and gas field in the Krasnoyarsk region to the settlement of Urengoi.
The aircraft crashed about 28 miles northeast outside of Urengoi, the Guardian said.
Poor weather conditions hampered search and rescue efforts but officials told the BBC that three survivors were rescued and taken for medical treatment.
A criminal investigation into the crash has been launched.
Investigators currently suspect that the crash was caused by poor weather conditions, flight safety violations or mechanical issues, the BBC said.
In a statement, the investigative committee told UPI that neither of those three theories are currently “regarded as most likely.”