Greenpeace personnel board Russia's Gazprom Prirazlomnaya platform in the Pechora Sea.
The activists aim at disrupting the platform’s operation and bring focus on climate change in the Arctic.
The activists set off in three inflatable speedboats from the Greenpeace ship "Arctic Sunrise" and scaled the platform via mooring lines. Six climbers have taken up positions on the structure and claim to have interrupted the platform's operations. Greenpeace say their people are out of reach and have enough supplies to last them for several days.
Russian energy giant Gazprom intends to begin full commercial drilling operations by early next year, becoming the first ever company to start commercial oil production in the offshore Arctic.
Executive Director of Greenpeace International, Kumi Naidoo said: “We climbed Gazprom's rusting oil platform backed by over a million people who have joined a new movement to protect the Arctic. We are here on their behalf.
Earlier Greenpeace discovered that the Gazprom platform is operating without an official oil spill response plan. Gazprom’s response plan was approved in July 2007 for a period of exactly five years. The Russian Ministry of Emergency admitted to Greenpeace in a letter that a new spill plan has been neither submitted nor approved.