At least 18 people were killed in a helicopter crash in the Krasnoyarsk region in Siberia on Saturday, the aviation watchdog and emergency services said.
"There were three crew members and 15 passengers overseas the Mi-8 that belonged to Utair airline", an emergency services official told TASS news agency.
The dead were working for a subsidiary of oil giant Rosneft in the remote Vankor oil field, which is above the Arctic Circle.
The second aircraft landed safely and the accident took place in "normal" weather conditions, according to preliminary findings.
"The first take-off was carried out by an Mi-8 with an external cargo suspension without passengers on board", the ministry said in a statement.
The helicopter was operated by Russian national airline Utair, which has its head office in Khanty Mansiysk airport in western Siberia.
The chopper was reportedly taking workers to an oil well.
The helicopter's black box flight recorders have been recovered and appear undamaged, Russian news agency TASS quoted law enforcement agencies as saying.
Accidents involving helicopters and small planes are frequent in Siberia and far eastern Russian Federation, where air transport is commonly used to cover vast distances.
The Emergencies Ministry was sending over a group of An-74 and Be-200 aircraft and 25 people from regional search and rescue centres to the site of the crash, according to the Krasnoyarsk region branch of the ministry.
The Mi-8 crashed to the ground seconds after takeoff and exploded in an inferno in the Krasnoyarsk region of Russian Federation.