The activists were detained by agents of the Russian Federal Security Service the day after what Greenpeace describes as a peaceful protest over the drilling activities of the Prirazlomnaya oil rig in the Arctic Pechora Sea.

"Once the protest ended, the activists, with the exception of the two brave climbers who were apprehended by Russian agents near the platform, returned to the Greenpeace ship, the Arctic Sunrise," Greenpeace legal representatives Sergey Golubok and Kristin Casper said in a statement.

"The Russian agents' violent response breached their rights to freedom of expression and has a chilling effect on future peaceful protests aimed at protecting the Arctic.

"What followed was a gross violation of the right to liberty.

"The next day, armed agents of the Russian Federal Security Service boarded the Arctic Sunrise from a helicopter and detained the individuals on board.

"The Arctic Sunrise was in the exclusive economic zone of the Russian Federation in the Pechora Sea and outside of the Russian-declared three nautical miles exclusion zone around the oil platform, Prirazlomnaya, which was the target of the protest."

Greenpeace says the Arctic 30 are requesting "just compensation" from the Russian Federation, as well as a statement from the independent court saying that their apprehension in international waters by Russian agents and subsequent detention was unlawful.

All 30 were charged with piracy, a charge later remodelled as "hooliganism" after the head of the Investigative Committee for the Russian Federation ruled that piracy was an improper charge.