Russian coast guards on Wednesday arrested two Greenpeace activists who scaled an oil platform owned by state energy giant Gazprom in the Arctic to protest oil drilling in defiance of warning shots, the environmental group and officials said. The activists set off before dawn in inflatables launched by Greenpeace mothership the Arctic Sunrise and headed towards Gazprom\'s Prirazlomnaya oil rig in the Pechora Sea, Greenpeace said in a statement. The Russian coastguard managed to arrest two activists but two others were able to attach themselves to the platform with ropes, defying freezing cold water hosed down on them from the platform. However the two activists who climbed up the platform were themselves arrested and taken into custody on board the coastguard vessel, Greenpeace said. Greenpeace said that the coastguards fired 11 warning shots across the Arctic Sunrise but said the vessel would remain in the area. It condemned a \"disproportionate\" use of force by the coast guards in response to a \"peaceful protest\". Russian\'s Federal Security Service confirmed in a statement that its coastguards had fired warning shots from an AK-74 Kalashnikov assault rifle in response to the refusal of the ecologists to halt their \"illegal activities\" despite verbal warnings. It confirmed that two activists had been detained and said their identities still had to be confirmed. The FSB said it had also ordered the Arctic Sunrise to come to a halt and the coastguards had fired another four artillery shots but the vessel had refused to stop. Greenpeace said the coastguards had asked to board the ship but were refused permission by the ship\'s captain. Greenpeace said that Gazprom intends to start production from the Prirazlomnaya platform in 2014, raising the risk of an oil spill in an area with three nature reserves that is home to polar bears, walruses and rare seabirds. \"This rusty oil platform is an Arctic disaster waiting to happen,\" said Greenpeace activist Sini Saarela in a statement. The world\'s largest gas firm, Gazprom has expanded its oil production operations in recent years and describes the Prirazlomnoye oil field as an essential element of its oil business development strategy. Russian and foreign environmentalists regularly accuse Gazprom and other big Russian energy firms of turning a blind eye to ecological concerns as they seek to find energy resources in ever more remote locations. However the Russian energy firms insist they fully adhere to environmental regulations during exploration and production operations. Gazprom declined to comment on the situation.