MOSCOW - Russian authorities charged Greenpeace activists from several nations with piracy on Wednesday over a protest against Arctic oil drilling at a platform owned by the state-controlled energy company Gazprom, the environmental group said.
The piracy charges, which Greenpeace said were absurd, are punishable by up to 15 years in prison.
The federal Investigative Committee said authorities had begun charging 30 people arrested after the protest last month, in which a Greenpeace icebreaker approached the Prirazlomnaya platform and two activists tried to scale the rig - a crucial part of Russia's effort to mine Arctic resources.
By midday, five people had been charged, Greenpeace said - Brazilian crew member Ana Paula Alminhana, Russian activist Roman Dolgov, Finnish activist Sini Saarela, British freelance videographer Kieron Bryan, and Dima Litvinov, an activist with Swedish and US citizenship.
"It is an extreme and disproportionate charge," Greenpeace International executive director Kumi Naidoo said.
"A charge of piracy is being laid against men and women whose only crime is to be possessed of a conscience. This is an outrage and represents nothing less than an assault on the very principle of peaceful protest."
A court in the northern city of Murmansk last week ordered all 30 people from 18 countries who had been aboard the Greenpeace icebreaker Arctic Sunrise to be held in custody for two months pending further investigation.
The Investigative Committee said authorities had begun to charge the activists on Wednesday but gave no details.
The environmental group says the protest was peaceful and posed no threat, and that piracy charges have no merit in international or Russian law.
President Vladimir Putin said last week the protesters were clearly not pirates but they had violated international law.
The Investigative Committee said on Monday peaceful aims would not justify what it has called an "attack" that posed a threat to the platform and its personnel.
Prirazlomnaya, Russia's first offshore oil rig in the Arctic, is slated to start operating by the end of the year and is expected to reach peak production of 6 million tonnes per year (120,000 barrels per day) in 2019.
Russia, whose slowing economy is heavily reliant on income from energy exports, hopes Arctic oil and gas will help fuel future growth.
Putin, whose current term ends in 2018, has described Arctic shipping and development and last moth announced plans to reopen a Soviet-era military base in the region.
Greenpeace says scientific evidence shows any oil spill from Prirazlomnaya, in the Pechora Sea, would affect more than 3,000 miles of Russia's northern coastline.
Naidoo called Russia's treatment of the protesters "the most serious threat to Greenpeace's peaceful environmental activism" since its ship Rainbow Warrior was bombed and sunk while in port in New Zealand in 1985, when the group was protesting French nuclear testing in the Pacific.