MOSCOW -- A Russian helicopter crashed shortly after takeoff in Siberia on Saturday, killing all 18 people aboard. The Mi-8 helicopter collided with a load being carried by another helicopter that had taken off from the same pad in Vankor, above the Arctic Circle about 1,600 miles northeast of Moscow, according to the Interstate Aviation Committee, which oversees civil aviation in much of the former Soviet Union.

There were 15 passengers and three crew aboard the crashed helicopter, said a statement from the operator, UTair airlines.

The second helicopter was undamaged and landed safely, the committee said.

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Helicopters frequently carry loads in slings that hang below the craft.

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

Authorities were investigating allegations of negligence and looking into whether any safety guidelines were violated, said Svetlana Petrenko, a government official, BBC News reported.

The Russian Transport Ministry has said that the crash occurred in "normal" weather conditions.

UTair, one of Russia's largest airlines, operates an extensive fleet of helicopters serving Siberian oil fields as well as fixed-wing flights within Russia and to international destinations, mostly in former Soviet republics.

The helicopter that crashed was manufactured in 2010 and the pilot had nearly 6,000 hours of experience, including 2,300 as a captain, the UTair statement said.

Russian air safety has improved since the 1990s, when poor aircraft maintenance, pilot training and official oversight in the wake of the collapse of the Soviet Union resulted in a high crash incidence.

In February, a Saratov Airlines An-148 regional jet crashed about six minutes after takeoff from Moscow's Domodedovo Airport, killing all 71 people aboard. Investigators said the crew had failed to turn on a heating unit, resulting in flawed airspeed readings. A UTair ATR 72 crashed in Siberia in 2012, killing 33 of the 43 people aboard, after failing to be de-iced before takeoff.