Russian officials say environmental activists who conducted a protest at an Arctic oil platform last week will be prosecuted regardless of citizenship.
Security forces stormed the vessel in a dramatic helicopter operation last Friday after two of the activists from the Greenpeace ship Arctic Sunrise tried scaling an oil rig in a protest against Arctic drilling.
Russia's Federal Investigative Committee says it has opened a criminal case against the 25 activists, including two New Zealanders, on suspicion of piracy.
The charge, which Greenpeace has called a joke, carries a sentence of up to 15 years' jail.
The committee said in a statement the "attack" on Gazprom's Prirazlomnaya platform, Russia's first offshore Arctic oil platform, had threatened environmental damage to the region and violated Russian sovereignty, Reuters reports.
"When a foreign ship full of electronic equipment intended for unknown purposes and a group of people, declaring themselves to be environmental activists, try to storm a drilling platform there are legitimate doubts about their intentions," said the statement.
The protest ended in the arrest of the activists and the detention of their Netherlands-registered vessel. Russian authorities were towing the Arctic Sunrise toward the Arctic port of Murmansk on Tuesday.
Greenpeace says Russia's actions violated international law and has demanded the immediate release of the activists, Reuters reports. The group says the protesters had been denied access to lawyers and consular officials for four days.