COPENHAGEN, Denmark (AP) — A Russian helicopter with eight people on board crashed on Thursday into the frigid sea off Svalbard, an Arctic archipelago that belongs to Norway, rescue officials said.

The rescue service for northern Norway says the helicopter was en route to Barentsburg, Svalbard's second-largest settlement, from the Russian settlement of Pyramiden.

"We have found oil on the water but no wreck," Olav Bjoergaas, a spokesman for the Joint Rescue Coordination Centers for northern Norway, told The Associated Press. He added that there was poor visibility and heavy snowfall in the region.

Svalbard is more than 800 kilometers (500 miles) north of Norway's mainland. It's known for stunning views of snow-covered mountains, fjords and glaciers.

Barentsburg is a Russian coal-mining town of about 500 people. Under a 1920 treaty, Norway has sovereignty over the archipelago but other signatory countries have rights to exploit its natural resources.

Pyramiden also was a Russian mining settlement, but was largely abandoned in 1998. It attracts some tourists on excursions to see the empty Soviet-era buildings and the world's northernmost monument to Vladimir Lenin.

The rescue service said the helicopter went down 2 to 3 kilometers (1.3 to 1.9 miles) from Barentsburg at 3.30 p.m.

The Mi-8 helicopter belonged to Russian coal company Arktikugol but was operated by charter company Konvers Avia, the Russian Energy Ministry said in a statement.

It said the eight people aboard were five crew members and three staff members from Russia's national Arctic and Antarctic Research Institute.

Tore Hongset, another spokesman for the rescue coordination center, told Norwegian news agency NTB that it did not receive any mayday signal from the helicopter.

"As far as we have heard, we are talking about a crash," Hongset said.

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. Local hospitals were on high alert.

In March 2008, three people were killed after a Russian Mi-8 helicopter with nine people on board crashed about 4 kilometers (2.5 miles) from Barentsburg.

In August 1996, a Russian plane carrying residents of Barentsburg and Pyramiden crashed on approach to the Svalbard Airport, killing all 141 people aboard.

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Jim Heintz in Moscow contributed to this report.