The Russian Coast Guard arrested two Greenpeace activists after members of the international environmentalist group scaled an oil platform Wednesday in the Barents Sea, and the Coast Guard fired warning shots at one of the group's vessels, according to the Guardian.

Greenpeace said in an emailed message that it sent five vessels to the Prirazlomnaya platform, which is operated by Kremlin-controlled OAO Gazprom (MCX:GAZP), triggering gunfire -- at least 11 shots reportedly were fired -- from the Coast Guard at the Arctic Sunrise, Greenpeace's icebreaker. 

"Due to the refusal of the Arctic Sunrise captain to halt the unlawful activity, the administration took a decision to stop the ship. The coast guard was forced to fire warning shots four times from an artillery cannon onboard a vessel," the Russian Federal Security Service said.

This is not the first time the Arctic Sunrise was confronted by the Russian Coast Guard. In late August, the Coast Guard boarded the Sunrise after activists protested drilling by Exxon Mobil Corporation (NYSE:XOM) and Rosneft NK OAO (MCX:ROSN) in the Kara Sea.

Last month, Christie Ferguson, the lead Arctic campaigner for Greenpeace, said that the Russian Coast Guard threatened its ship with gunfire if they did not leave the Northern Sea route area. Ben Ben Ayliffe, the head of Greenpeace International’s Arctic oil campaign, said in a statement that the “real threat to the Arctic comes not from Greenpeace International but from oil companies like Gazprom that are determined to ignore both science and good sense to drill in remote, frozen seas.”

Prirazlomnaya is the first offshore oil deposit in the Arctic Sea to be developed by Gazprom. It is located in the Pechora Sea, which is part of the Barents Sea.