The helicopter was reported missing at 3.35 p.m. and confirmed having gone down at 3.45 p.m. the Joint Rescue Coordination Centres (JRCC) in Northern Norway said on Twitter, Xinhua reported.
Russian helicopter has crashed into the sea off the Arctic island of Svalbard, Norway, according to the Norway rescue service.
The nationalities of the eight people on board are also unknown so far.
"We've only been informed that it went down at sea".
Several units, including two helicopters from the local Svalbard governor and ships from the coast guard and local fishermen were at the presumed crash site, Bjoergaas said.More news: Struggling Curtis Granderson left off Dodgers' World Series roster
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Barentsburg is the second-largest settlement on Svalbard, a Norwegian archipelago in the Arctic Ocean more than 500 miles north of the mainland.
The helicopter was en route from the mothballed community of Pyramiden to Barentsburg. "We don't know if it was a controlled landing", an emergency services spokesman told AFP.
"We are physically looking for the helicopter".
Nationals of all signatory states enjoy "equal liberty of access and entry" to Svalbard and its waters.
In March 2008, three people were killed after a Russian Mi-8 helicopter with nine people on board crashed about two miles from Barentsburg.