Greenpeace have released video footage of their ship, the Arctic Sunrise, being boarded and seized by Russian forces.
The footage appears to show Greenpeace activists attempting to block the ship's helipad with their own bodies to prevent a landing, before armed masked soldier rappel from the helicopter to seize the ship.
A group of 28 Greenpeace activists, a Russian photographer and a British videographer have been held since their ship was seized by the Russian coast guard after protesting outside a Gazprom-owned oil rig September 18.
The group was initially charged with piracy, but those charges were later dropped and replaced with hooliganism. Piracy carries a jail sentence of up to 15 years, while hooliganism is a much less serious offence with a custodial sentence of 15 days or a fine.
Dutch lawyers for the group have argued that the seizure was illegal under international regulations from the UN.