Russian investigators have charged all 30 crew members of Greenpeace's Arctic Sunrise ship with piracy after they staged a protest near a state-owned oil platform.
"All 30 participants in the criminal case have been charged over the attack on the Prirazlomnaya platform," the Investigative Committee said in a statement.
The group, made up mostly of foreign crew members from Greenpeace's Arctic Sunrise ship have been held in custody for the past two months and on Wednesday 14 were charged with piracy.
The remaining members were charged with piracy on Thursday, including the ship's support staff.
Piracy by an organised group carries a sentence of between 10 and 15 years in Russia. Investigators have accused them of trying to seize property by force.
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During a protest on September 18, several activists scaled Gazprom's Prirazlomnaya oil platform in the Barents Sea to denounce plans for drilling in the pristine Arctic.
Russian border guards then lowered themselves onto the Dutch-flagged Arctic Sunrise from a helicopter, locked up the crew and towed the icebreaker to Murmansk, nearly 2000km north of Moscow.
On Thursday, investigators charged seven more activists and Russian photojournalist Denis Sinyakov, who was working for Greenpeace on a freelance basis.
It appeared likely that all 30 activists - 26 of them foreigners - would be handed the same charge, even though the detainees included the ship's support staff.
Greenpeace has called the charges an "outrage".
The lawyers of all 30 activists have filed appeals against the court decisions to hold them in detention, a spokeswoman for Murmansk's Lenin district court told the RAPSI legal news agency.
The chairman of the presidential council on human rights, an advisory body, Mikhail Fedotov, told the Interfax news agency on Thursday that there was "not the slightest basis" for the piracy charge.
President Vladimir Putin has said that in his opinion, the activists were not pirates but had breached international law.
