A Russian helicopter crashed Sunday while attempting to land at the remote settlement of Barentsburg on Norway's Svalbard islands in the Arctic, killing three, rescue officials said.

There were six other people onboard the Mi8 helicopter and they were taken to a local clinic for treatment, said Sten Rune Nikolaisen, of the Norwegian rescue coordination center from northern Norway. The cause of the crash was not immediately known, he said by telephone.

Barentsburg is a Russian settlement of about 400 people allowed on the Norwegian islands under a 1920 treaty that declares the archipelago an international zone open to all countries for nonmilitary activities.

The Svalbard islands are about 300 miles north of the Norwegian mainland.

Two of the survivors will be brought to the nearby Norwegian settlement of Longyearbyen for treatment at the larger hospital in the town of about 2,000 people, Svalbard Gov. Per Sefland said.

"We understand the crash happened in connection with landing, and that the helicopter is completely crushed," Sefland said. "We have sent our own helicopter with police and medical personnel," he said, adding that the situation in the Russian area appears to be under control.

He said the helicopter crashed at about 4 p.m. local time.