Six Greenpeace members have boarded a Russian offshore oil rig in protest over gas and oil exploration in the Arctic.
The organisation says they reached the Prirazlomnaya platform in the Pechora Sea by speedboat early on Friday and have enough supplies to last several days.
It says drilling plans by Gazprom are "dangerous" and should be abandoned.
The BBC reports Gazprom is due to begin drilling next year for commercial oil production.
Greenpeace has previously occupied vessels operated by Shell and Cairn Energy over the issue.