Five meteorologists (气象学家) who were trapped for two weeks after polar bears surrounded their weather station are now able to leave after the creatures were chased away. Their supervisor told NBC News early Wednesday.

    Russian officials had feared the siege could last for another month, the time it would take to reach the islands in the Kara Sea, high in the Arctic Circle. But on Tuesday night a research ship took a detour (绕道) to assist those weathermen, station supervisor Vasily Shevchenko told NBC News. The ship run by Russia's state-run oil firm Rosneft frightened away the bears using its helicopter, before resupplying the weather station with more food and puppies (幼犬) . The puppies are not yet big enough todeterthe bears, but the station is planning to draft in a replacement adult guard dog as soon as possible.

    Some of the bears had taken to sleeping directly outside the windows of remote outpost. There was no risk of the researchers starving because they had a year's worth of food, but they were forced to take dangerous trips to a nearby building, holding a gun for protection, according to Shevchenko.

    Polar bears are an endangered species. In Russia, it's a crime to shoot them unless in self-defense. The bears usually leave the islands in the summer, but this time they were trapped by the melting ice, an apparent sign of climate change, according to Shevchenko. “They've stayed on the island because there is nowhere for them to go,” he said.

    The animals suffer from global warming because it shrinks the floating ice that forms their main hunting ground. According to the environmental group the World Wide Fund for Nature, known as the WWF, this has got some polar bears to go near human habitats in search of food.