Russian Prime Minister Vladimir Putin visited the country's northern Franz Josef Land archipelago islands, where he assisted members of a research expedition studying endangered polar bears.

Members of the Russian Institute of Ecology and Evolution expedition gave Putin a full round-up of the group's activities from their base on Alexandra Land, one of scores of ice-covered islands in the archipelago.

Putin helped researchers attach a collar - fitted with a radio transmitter - to a sedated polar bear. He also assisted as the giant bear was weighed and measured.

"The polar bear is in danger, there are only 25-thousand of them remaining in the world," Putin said.

Putin also called for a "general clean-up of the Arctic area", noting the build-up of manmade pollution.

He called for thousands of barrels of Soviet-era fuel littering the region to be removed: "According to different estimates there are between 40 and 60-thousand tonnes of fuel and lubricant materials stored here and pollution levels are six times higher than allowed," he said.