MOSCOW — A Russian airline says one of its helicopters has crashed shortly after takeoff in Siberia, killing all 18 people aboard.

The UTair airline, which operated the Mi-8 helicopter, said in a statement that preliminary information indicated the aircraft’s blades collided with another helicopter that had taken off earlier Saturday from the pad in Vankor, above the Arctic Circle about 1600 miles northeast of Moscow.

There were 15 passengers and three crew aboard, the airline said.

Russian news reports said all the passengers were believed to have been working for a subsidiary of the state oil company Rosneft.